pkbuff->iobuf changeover

Achieved via Perl using:

perl -pi -e 's/pk_buff/io_buffer/g; s/Packet buffer/I\/O buffer/ig; ' \
	-e 's/pkbuff\.h/iobuf.h/g; s/pkb_/iob_/g; s/_pkb/_iob/g; ' \
	-e 's/pkb/iobuf/g; s/PKB/IOB/g;'

25 files changed, 429 insertions, 665 deletions

diff --git a/src/arch/i386/drivers/net/undinet.c b/src/arch/i386/drivers/net/undinet.c
index 835ec76d..d54429bd 100644
--- a/src/arch/i386/drivers/net/undinet.c
+++ b/src/arch/i386/drivers/net/undinet.c
@@ -22,7 +22,7 @@
 #include <pic8259.h>
 #include <biosint.h>
 #include <pnpbios.h>
-#include <gpxe/pkbuff.h>
+#include <gpxe/iobuf.h>
 #include <gpxe/netdevice.h>
 #include <gpxe/if_ether.h>
 #include <gpxe/ethernet.h>
@@ -315,11 +315,11 @@ static int undinet_isr_triggered ( void ) {
  */
 
 /** Maximum length of a packet transmitted via the UNDI API */
-#define UNDI_PKB_LEN 1514
+#define UNDI_IOB_LEN 1514
 
-/** UNDI packet buffer */
-static char __data16_array ( undinet_pkb, [UNDI_PKB_LEN] );
-#define undinet_pkb __use_data16 ( undinet_pkb )
+/** UNDI I/O buffer */
+static char __data16_array ( undinet_iob, [UNDI_IOB_LEN] );
+#define undinet_iob __use_data16 ( undinet_iob )
 
 /** UNDI transmit buffer descriptor */
 static struct s_PXENV_UNDI_TBD __data16 ( undinet_tbd );
@@ -329,20 +329,20 @@ static struct s_PXENV_UNDI_TBD __data16 ( undinet_tbd );
  * Transmit packet
  *
  * @v netdev		Network device
- * @v pkb		Packet buffer
+ * @v iobuf		I/O buffer
  * @ret rc		Return status code
  */
 static int undinet_transmit ( struct net_device *netdev,
-			      struct pk_buff *pkb ) {
+			      struct io_buffer *iobuf ) {
 	struct undi_nic *undinic = netdev->priv;
 	struct s_PXENV_UNDI_TRANSMIT undi_transmit;
-	size_t len = pkb_len ( pkb );
+	size_t len = iob_len ( iobuf );
 	int rc;
 
-	/* Copy packet to UNDI packet buffer */
-	if ( len > sizeof ( undinet_pkb ) )
-		len = sizeof ( undinet_pkb );
-	memcpy ( &undinet_pkb, pkb->data, len );
+	/* Copy packet to UNDI I/O buffer */
+	if ( len > sizeof ( undinet_iob ) )
+		len = sizeof ( undinet_iob );
+	memcpy ( &undinet_iob, iobuf->data, len );
 
 	/* Create PXENV_UNDI_TRANSMIT data structure */
 	memset ( &undi_transmit, 0, sizeof ( undi_transmit ) );
@@ -357,7 +357,7 @@ static int undinet_transmit ( struct net_device *netdev,
 	undinet_tbd.ImmedLength = len;
 	undinet_tbd.Xmit.segment = rm_ds;
 	undinet_tbd.Xmit.offset 
-		= ( ( unsigned ) & __from_data16 ( undinet_pkb ) );
+		= ( ( unsigned ) & __from_data16 ( undinet_iob ) );
 
 	/* Issue PXE API call */
 	if ( ( rc = undinet_call ( undinic, PXENV_UNDI_TRANSMIT,
@@ -365,8 +365,8 @@ static int undinet_transmit ( struct net_device *netdev,
 				   sizeof ( undi_transmit ) ) ) != 0 )
 		goto done;
 
-	/* Free packet buffer */
-	netdev_tx_complete ( netdev, pkb );
+	/* Free I/O buffer */
+	netdev_tx_complete ( netdev, iobuf );
 
  done:
 	return rc;
@@ -397,7 +397,7 @@ static int undinet_transmit ( struct net_device *netdev,
 static void undinet_poll ( struct net_device *netdev, unsigned int rx_quota ) {
 	struct undi_nic *undinic = netdev->priv;
 	struct s_PXENV_UNDI_ISR undi_isr;
-	struct pk_buff *pkb = NULL;
+	struct io_buffer *iobuf = NULL;
 	size_t len;
 	size_t frag_len;
 	int rc;
@@ -448,26 +448,26 @@ static void undinet_poll ( struct net_device *netdev, unsigned int rx_quota ) {
 			/* Packet fragment received */
 			len = undi_isr.FrameLength;
 			frag_len = undi_isr.BufferLength;
-			if ( ! pkb )
-				pkb = alloc_pkb ( len );
-			if ( ! pkb ) {
+			if ( ! iobuf )
+				iobuf = alloc_iob ( len );
+			if ( ! iobuf ) {
 				DBGC ( undinic, "UNDINIC %p could not "
 				       "allocate %zd bytes for RX buffer\n",
 				       undinic, len );
 				/* Fragment will be dropped */
 				goto done;
 			}
-			if ( frag_len > pkb_tailroom ( pkb ) ) {
+			if ( frag_len > iob_tailroom ( iobuf ) ) {
 				DBGC ( undinic, "UNDINIC %p fragment too "
 				       "large\n", undinic );
-				frag_len = pkb_tailroom ( pkb );
+				frag_len = iob_tailroom ( iobuf );
 			}
-			copy_from_real ( pkb_put ( pkb, frag_len ),
+			copy_from_real ( iob_put ( iobuf, frag_len ),
 					 undi_isr.Frame.segment,
 					 undi_isr.Frame.offset, frag_len );
-			if ( pkb_len ( pkb ) == len ) {
-				netdev_rx ( netdev, pkb );
-				pkb = NULL;
+			if ( iob_len ( iobuf ) == len ) {
+				netdev_rx ( netdev, iobuf );
+				iobuf = NULL;
 				--rx_quota;
 			}
 			break;
@@ -486,10 +486,10 @@ static void undinet_poll ( struct net_device *netdev, unsigned int rx_quota ) {
 	}
 
  done:
-	if ( pkb ) {
+	if ( iobuf ) {
 		DBGC ( undinic, "UNDINIC %p returned incomplete packet\n",
 		       undinic );
-		netdev_rx ( netdev, pkb );
+		netdev_rx ( netdev, iobuf );
 	}
 }
 
diff --git a/src/drivers/net/legacy.c b/src/drivers/net/legacy.c
index d9bae1d7..27d225a4 100644
--- a/src/drivers/net/legacy.c
+++ b/src/drivers/net/legacy.c
@@ -4,7 +4,7 @@
 #include <gpxe/if_ether.h>
 #include <gpxe/netdevice.h>
 #include <gpxe/ethernet.h>
-#include <gpxe/pkbuff.h>
+#include <gpxe/iobuf.h>
 #include <nic.h>
 
 /*
@@ -21,38 +21,38 @@ struct nic nic;
 
 static int legacy_registered = 0;
 
-static int legacy_transmit ( struct net_device *netdev, struct pk_buff *pkb ) {
+static int legacy_transmit ( struct net_device *netdev, struct io_buffer *iobuf ) {
 	struct nic *nic = netdev->priv;
-	struct ethhdr *ethhdr = pkb->data;
+	struct ethhdr *ethhdr = iobuf->data;
 
-	DBG ( "Transmitting %d bytes\n", pkb_len ( pkb ) );
-	pkb_pad ( pkb, ETH_ZLEN );
-	pkb_pull ( pkb, sizeof ( *ethhdr ) );
+	DBG ( "Transmitting %d bytes\n", iob_len ( iobuf ) );
+	iob_pad ( iobuf, ETH_ZLEN );
+	iob_pull ( iobuf, sizeof ( *ethhdr ) );
 	nic->nic_op->transmit ( nic, ( const char * ) ethhdr->h_dest,
 				ntohs ( ethhdr->h_protocol ),
-				pkb_len ( pkb ), pkb->data );
-	netdev_tx_complete ( netdev, pkb );
+				iob_len ( iobuf ), iobuf->data );
+	netdev_tx_complete ( netdev, iobuf );
 	return 0;
 }
 
 static void legacy_poll ( struct net_device *netdev, unsigned int rx_quota ) {
 	struct nic *nic = netdev->priv;
-	struct pk_buff *pkb;
+	struct io_buffer *iobuf;
 
 	if ( ! rx_quota )
 		return;
 
-	pkb = alloc_pkb ( ETH_FRAME_LEN );
-	if ( ! pkb )
+	iobuf = alloc_iob ( ETH_FRAME_LEN );
+	if ( ! iobuf )
 		return;
 
-	nic->packet = pkb->data;
+	nic->packet = iobuf->data;
 	if ( nic->nic_op->poll ( nic, 1 ) ) {
 		DBG ( "Received %d bytes\n", nic->packetlen );
-		pkb_put ( pkb, nic->packetlen );
-		netdev_rx ( netdev, pkb );
+		iob_put ( iobuf, nic->packetlen );
+		netdev_rx ( netdev, iobuf );
 	} else {
-		free_pkb ( pkb );
+		free_iob ( iobuf );
 	}
 }
 
diff --git a/src/drivers/net/pnic.c b/src/drivers/net/pnic.c
index 7f442420..95571961 100644
--- a/src/drivers/net/pnic.c
+++ b/src/drivers/net/pnic.c
@@ -19,7 +19,7 @@ Bochs Pseudo NIC driver for Etherboot
 #include <gpxe/pci.h>
 #include <gpxe/if_ether.h>
 #include <gpxe/ethernet.h>
-#include <gpxe/pkbuff.h>
+#include <gpxe/iobuf.h>
 #include <gpxe/netdevice.h>
 
 #include "pnic_api.h"
@@ -114,7 +114,7 @@ POLL - Wait for a frame
 ***************************************************************************/
 static void pnic_poll ( struct net_device *netdev, unsigned int rx_quota ) {
 	struct pnic *pnic = netdev->priv;
-	struct pk_buff *pkb;
+	struct io_buffer *iobuf;
 	uint16_t length;
 	uint16_t qlen;
 
@@ -126,19 +126,19 @@ static void pnic_poll ( struct net_device *netdev, unsigned int rx_quota ) {
 			break;
 		if ( qlen == 0 )
 			break;
-		pkb = alloc_pkb ( ETH_FRAME_LEN );
-		if ( ! pkb ) {
+		iobuf = alloc_iob ( ETH_FRAME_LEN );
+		if ( ! iobuf ) {
 			printf ( "could not allocate buffer\n" );
 			break;
 		}
 		if ( pnic_command ( pnic, PNIC_CMD_RECV, NULL, 0,
-				    pkb->data, ETH_FRAME_LEN, &length )
+				    iobuf->data, ETH_FRAME_LEN, &length )
 		     != PNIC_STATUS_OK ) {
-			free_pkb ( pkb );
+			free_iob ( iobuf );
 			break;
 		}
-		pkb_put ( pkb, length );
-		netdev_rx ( netdev, pkb );
+		iob_put ( iobuf, length );
+		netdev_rx ( netdev, iobuf );
 		--rx_quota;
 	}
 }
@@ -146,17 +146,17 @@ static void pnic_poll ( struct net_device *netdev, unsigned int rx_quota ) {
 /**************************************************************************
 TRANSMIT - Transmit a frame
 ***************************************************************************/
-static int pnic_transmit ( struct net_device *netdev, struct pk_buff *pkb ) {
+static int pnic_transmit ( struct net_device *netdev, struct io_buffer *iobuf ) {
 	struct pnic *pnic = netdev->priv;
 
 	/* Pad the packet */
-	pkb_pad ( pkb, ETH_ZLEN );
+	iob_pad ( iobuf, ETH_ZLEN );
 
 	/* Send packet */
-	pnic_command ( pnic, PNIC_CMD_XMIT, pkb->data, pkb_len ( pkb ),
+	pnic_command ( pnic, PNIC_CMD_XMIT, iobuf->data, iob_len ( iobuf ),
 		       NULL, 0, NULL );
 
-	netdev_tx_complete ( netdev, pkb );
+	netdev_tx_complete ( netdev, iobuf );
 	return 0;
 }
 
diff --git a/src/drivers/net/rtl8139.c b/src/drivers/net/rtl8139.c
index d3b89223..548a6931 100644
--- a/src/drivers/net/rtl8139.c
+++ b/src/drivers/net/rtl8139.c
@@ -76,7 +76,7 @@
 #include <gpxe/pci.h>
 #include <gpxe/if_ether.h>
 #include <gpxe/ethernet.h>
-#include <gpxe/pkbuff.h>
+#include <gpxe/iobuf.h>
 #include <gpxe/netdevice.h>
 #include <gpxe/spi_bit.h>
 #include <gpxe/threewire.h>
@@ -86,7 +86,7 @@
 
 struct rtl8139_tx {
 	unsigned int next;
-	struct pk_buff *pkb[TX_RING_SIZE];
+	struct io_buffer *iobuf[TX_RING_SIZE];
 };
 
 struct rtl8139_rx {
@@ -363,28 +363,28 @@ static void rtl_close ( struct net_device *netdev ) {
  * Transmit packet
  *
  * @v netdev	Network device
- * @v pkb	Packet buffer
+ * @v iobuf	I/O buffer
  * @ret rc	Return status code
  */
-static int rtl_transmit ( struct net_device *netdev, struct pk_buff *pkb ) {
+static int rtl_transmit ( struct net_device *netdev, struct io_buffer *iobuf ) {
 	struct rtl8139_nic *rtl = netdev->priv;
 
 	/* Check for space in TX ring */
-	if ( rtl->tx.pkb[rtl->tx.next] != NULL ) {
+	if ( rtl->tx.iobuf[rtl->tx.next] != NULL ) {
 		printf ( "TX overflow\n" );
 		return -ENOBUFS;
 	}
 
 	/* Pad and align packet */
-	pkb_pad ( pkb, ETH_ZLEN );
+	iob_pad ( iobuf, ETH_ZLEN );
 
 	/* Add to TX ring */
 	DBG ( "TX id %d at %lx+%x\n", rtl->tx.next,
-	      virt_to_bus ( pkb->data ), pkb_len ( pkb ) );
-	rtl->tx.pkb[rtl->tx.next] = pkb;
-	outl ( virt_to_bus ( pkb->data ),
+	      virt_to_bus ( iobuf->data ), iob_len ( iobuf ) );
+	rtl->tx.iobuf[rtl->tx.next] = iobuf;
+	outl ( virt_to_bus ( iobuf->data ),
 	       rtl->ioaddr + TxAddr0 + 4 * rtl->tx.next );
-	outl ( ( ( ( TX_FIFO_THRESH & 0x7e0 ) << 11 ) | pkb_len ( pkb ) ),
+	outl ( ( ( ( TX_FIFO_THRESH & 0x7e0 ) << 11 ) | iob_len ( iobuf ) ),
 	       rtl->ioaddr + TxStatus0 + 4 * rtl->tx.next );
 	rtl->tx.next = ( rtl->tx.next + 1 ) % TX_RING_SIZE;
 
@@ -403,7 +403,7 @@ static void rtl_poll ( struct net_device *netdev, unsigned int rx_quota ) {
 	unsigned int tsad;
 	unsigned int rx_status;
 	unsigned int rx_len;
-	struct pk_buff *rx_pkb;
+	struct io_buffer *rx_iob;
 	int wrapped_len;
 	int i;
 
@@ -416,10 +416,10 @@ static void rtl_poll ( struct net_device *netdev, unsigned int rx_quota ) {
 	/* Handle TX completions */
 	tsad = inw ( rtl->ioaddr + TxSummary );
 	for ( i = 0 ; i < TX_RING_SIZE ; i++ ) {
-		if ( ( rtl->tx.pkb[i] != NULL ) && ( tsad & ( 1 << i ) ) ) {
+		if ( ( rtl->tx.iobuf[i] != NULL ) && ( tsad & ( 1 << i ) ) ) {
 			DBG ( "TX id %d complete\n", i );
-			netdev_tx_complete ( netdev, rtl->tx.pkb[i] );
-			rtl->tx.pkb[i] = NULL;
+			netdev_tx_complete ( netdev, rtl->tx.iobuf[i] );
+			rtl->tx.iobuf[i] = NULL;
 		}
 	}
 
@@ -433,8 +433,8 @@ static void rtl_poll ( struct net_device *netdev, unsigned int rx_quota ) {
 			DBG ( "RX packet at offset %x+%x\n", rtl->rx.offset,
 			      rx_len );
 
-			rx_pkb = alloc_pkb ( rx_len );
-			if ( ! rx_pkb ) {
+			rx_iob = alloc_iob ( rx_len );
+			if ( ! rx_iob ) {
 				/* Leave packet for next call to poll() */
 				break;
 			}
@@ -444,13 +444,13 @@ static void rtl_poll ( struct net_device *netdev, unsigned int rx_quota ) {
 			if ( wrapped_len < 0 )
 				wrapped_len = 0;
 
-			memcpy ( pkb_put ( rx_pkb, rx_len - wrapped_len ),
+			memcpy ( iob_put ( rx_iob, rx_len - wrapped_len ),
 				 rtl->rx.ring + rtl->rx.offset + 4,
 				 rx_len - wrapped_len );
-			memcpy ( pkb_put ( rx_pkb, wrapped_len ),
+			memcpy ( iob_put ( rx_iob, wrapped_len ),
 				 rtl->rx.ring, wrapped_len );
 
-			netdev_rx ( netdev, rx_pkb );
+			netdev_rx ( netdev, rx_iob );
 			rx_quota--;
 		} else {
 			DBG ( "RX bad packet (status %#04x len %d)\n",
diff --git a/src/include/gpxe/ip.h b/src/include/gpxe/ip.h
index d212b3ef..9a5b7a81 100644
--- a/src/include/gpxe/ip.h
+++ b/src/include/gpxe/ip.h
@@ -25,7 +25,7 @@
 #define IP_TOS		0
 #define IP_TTL		64
 
-#define IP_FRAG_PKB_SIZE	1500
+#define IP_FRAG_IOB_SIZE	1500
 #define IP_FRAG_TIMEOUT		50
 
 /* IP4 pseudo header */
@@ -63,15 +63,15 @@ struct frag_buffer {
 	struct in_addr src;
 	/* Destination network address */
 	struct in_addr dest;
-	/* Reassembled packet buffer */
-	struct pk_buff *frag_pkb;
+	/* Reassembled I/O buffer */
+	struct io_buffer *frag_iob;
 	/* Reassembly timer */
 	struct retry_timer frag_timer;
 	/* List of fragment reassembly buffers */
 	struct list_head list;
 };
 
-struct pk_buff;
+struct io_buffer;
 struct net_device;
 struct net_protocol;
 struct tcpip_protocol;
diff --git a/src/include/gpxe/ip6.h b/src/include/gpxe/ip6.h
index 0ba17120..37c0781d 100644
--- a/src/include/gpxe/ip6.h
+++ b/src/include/gpxe/ip6.h
@@ -16,12 +16,12 @@
 #define IP6_HOP_LIMIT	255
 
 /**
- * Packet buffer contents
- * This is duplicated in tcp.h and here. Ideally it should go into pkbuff.h
+ * I/O buffer contents
+ * This is duplicated in tcp.h and here. Ideally it should go into iobuf.h
  */
 #define MAX_HDR_LEN	100
-#define MAX_PKB_LEN	1500
-#define MIN_PKB_LEN	MAX_HDR_LEN + 100 /* To account for padding by LL */
+#define MAX_IOB_LEN	1500
+#define MIN_IOB_LEN	MAX_HDR_LEN + 100 /* To account for padding by LL */
 
 #define IP6_EQUAL( in6_addr1, in6_addr2 ) \
         ( strncmp ( ( char* ) &( in6_addr1 ), ( char* ) &( in6_addr2 ),\
@@ -61,7 +61,7 @@ struct ipv6_pseudo_header {
 #define IP6_ICMP6		0x58
 #define IP6_NO_HEADER		0x59
 
-struct pk_buff;
+struct io_buffer;
 struct net_device;
 struct net_protocol;
 
diff --git a/src/include/gpxe/ndp.h b/src/include/gpxe/ndp.h
index ed9411f9..e3711b5d 100644
--- a/src/include/gpxe/ndp.h
+++ b/src/include/gpxe/ndp.h
@@ -6,7 +6,7 @@
 #include <gpxe/ip6.h>
 #include <gpxe/in.h>
 #include <gpxe/netdevice.h>
-#include <gpxe/pkbuff.h>
+#include <gpxe/iobuf.h>
 #include <gpxe/tcpip.h>
 
 #define NDP_STATE_INVALID 0
@@ -19,5 +19,5 @@
 static struct ndp_entry * ndp_find_entry ( struct in6_addr *in6 );
 int ndp_resolve ( struct net_device *netdev, struct in6_addr *src,
 		  struct in6_addr *dest, void *dest_ll_addr );
-int ndp_process_advert ( struct pk_buff *pkb, struct sockaddr_tcpip *st_src,
+int ndp_process_advert ( struct io_buffer *iobuf, struct sockaddr_tcpip *st_src,
 			 struct sockaddr_tcpip *st_dest );
diff --git a/src/include/gpxe/netdevice.h b/src/include/gpxe/netdevice.h
index f9d507bf..c71c0928 100644
--- a/src/include/gpxe/netdevice.h
+++ b/src/include/gpxe/netdevice.h
@@ -12,7 +12,7 @@
 #include <gpxe/tables.h>
 #include <gpxe/hotplug.h>
 
-struct pk_buff;
+struct io_buffer;
 struct net_device;
 struct net_protocol;
 struct ll_protocol;
@@ -37,13 +37,13 @@ struct net_protocol {
 	/**
 	 * Process received packet
 	 *
-	 * @v pkb	Packet buffer
+	 * @v iobuf	I/O buffer
 	 * @v netdev	Network device
 	 * @v ll_source	Link-layer source address
 	 *
-	 * This method takes ownership of the packet buffer.
+	 * This method takes ownership of the I/O buffer.
 	 */
-	int ( * rx ) ( struct pk_buff *pkb, struct net_device *netdev,
+	int ( * rx ) ( struct io_buffer *iobuf, struct net_device *netdev,
 		       const void *ll_source );
 	/**
 	 * Transcribe network-layer address
@@ -77,7 +77,7 @@ struct ll_protocol {
 	/**
 	 * Transmit network-layer packet via network device
 	 *
-	 * @v pkb		Packet buffer
+	 * @v iobuf		I/O buffer
 	 * @v netdev		Network device
 	 * @v net_protocol	Network-layer protocol
 	 * @v ll_dest		Link-layer destination address
@@ -85,15 +85,15 @@ struct ll_protocol {
 	 *
 	 * This method should prepend in the link-layer header
 	 * (e.g. the Ethernet DIX header) and transmit the packet.
-	 * This method takes ownership of the packet buffer.
+	 * This method takes ownership of the I/O buffer.
 	 */
-	int ( * tx ) ( struct pk_buff *pkb, struct net_device *netdev,
+	int ( * tx ) ( struct io_buffer *iobuf, struct net_device *netdev,
 		       struct net_protocol *net_protocol,
 		       const void *ll_dest );
 	/**
 	 * Handle received packet
 	 *
-	 * @v pkb	Packet buffer
+	 * @v iobuf	I/O buffer
 	 * @v netdev	Network device
 	 *
 	 * This method should strip off the link-layer header
@@ -101,7 +101,7 @@ struct ll_protocol {
 	 * net_rx().  This method takes ownership of the packet
 	 * buffer.
 	 */
-	int ( * rx ) ( struct pk_buff *pkb, struct net_device *netdev );
+	int ( * rx ) ( struct io_buffer *iobuf, struct net_device *netdev );
 	/**
 	 * Transcribe link-layer address
 	 *
@@ -151,7 +151,7 @@ struct net_device {
 	 * @v netdev	Network device
 	 * @ret rc	Return status code
 	 *
-	 * This method should allocate RX packet buffers and enable
+	 * This method should allocate RX I/O buffers and enable
 	 * the hardware to start transmitting and receiving packets.
 	 */
 	int ( * open ) ( struct net_device *netdev );
@@ -166,22 +166,22 @@ struct net_device {
 	/** Transmit packet
 	 *
 	 * @v netdev	Network device
-	 * @v pkb	Packet buffer
+	 * @v iobuf	I/O buffer
 	 * @ret rc	Return status code
 	 *
 	 * This method should cause the hardware to initiate
-	 * transmission of the packet buffer.
+	 * transmission of the I/O buffer.
 	 *
-	 * If this method returns success, the packet buffer remains
+	 * If this method returns success, the I/O buffer remains
 	 * owned by the net device's TX queue, and the net device must
 	 * eventually call netdev_tx_complete() to free the buffer.
-	 * If this method returns failure, the packet buffer is
+	 * If this method returns failure, the I/O buffer is
 	 * immediately released.
 	 *
 	 * This method is guaranteed to be called only when the device
 	 * is open.
 	 */
-	int ( * transmit ) ( struct net_device *netdev, struct pk_buff *pkb );
+	int ( * transmit ) ( struct net_device *netdev, struct io_buffer *iobuf );
 	/** Poll for received packet
 	 *
 	 * @v netdev	Network device
@@ -251,12 +251,12 @@ static inline int have_netdevs ( void ) {
 	return ( ! list_empty ( &net_devices ) );
 }
 
-extern int netdev_tx ( struct net_device *netdev, struct pk_buff *pkb );
-void netdev_tx_complete ( struct net_device *netdev, struct pk_buff *pkb );
+extern int netdev_tx ( struct net_device *netdev, struct io_buffer *iobuf );
+void netdev_tx_complete ( struct net_device *netdev, struct io_buffer *iobuf );
 void netdev_tx_complete_next ( struct net_device *netdev );
-extern void netdev_rx ( struct net_device *netdev, struct pk_buff *pkb );
+extern void netdev_rx ( struct net_device *netdev, struct io_buffer *iobuf );
 extern int netdev_poll ( struct net_device *netdev, unsigned int rx_quota );
-extern struct pk_buff * netdev_rx_dequeue ( struct net_device *netdev );
+extern struct io_buffer * netdev_rx_dequeue ( struct net_device *netdev );
 extern struct net_device * alloc_netdev ( size_t priv_size );
 extern int register_netdev ( struct net_device *netdev );
 extern int netdev_open ( struct net_device *netdev );
@@ -266,9 +266,9 @@ extern void free_netdev ( struct net_device *netdev );
 struct net_device * find_netdev ( const char *name );
 struct net_device * find_pci_netdev ( unsigned int busdevfn );
 
-extern int net_tx ( struct pk_buff *pkb, struct net_device *netdev,
+extern int net_tx ( struct io_buffer *iobuf, struct net_device *netdev,
 		    struct net_protocol *net_protocol, const void *ll_dest );
-extern int net_rx ( struct pk_buff *pkb, struct net_device *netdev,
+extern int net_rx ( struct io_buffer *iobuf, struct net_device *netdev,
 		    uint16_t net_proto, const void *ll_source );
 
 #endif /* _GPXE_NETDEVICE_H */
diff --git a/src/include/gpxe/pkbuff.h b/src/include/gpxe/pkbuff.h
deleted file mode 100644
index 85bcc036..00000000
--- a/src/include/gpxe/pkbuff.h
+++ /dev/null
@@ -1,163 +0,0 @@
-#ifndef _GPXE_PKBUFF_H
-#define _GPXE_PKBUFF_H
-
-/** @file
- *
- * Packet buffers
- *
- * Packet buffers are used to contain network packets.  Methods are
- * provided for appending, prepending, etc. data.
- *
- */
-
-#include <stdint.h>
-#include <assert.h>
-#include <gpxe/list.h>
-
-/**
- * Packet buffer alignment
- *
- * Packet buffers allocated via alloc_pkb() are guaranteed to be
- * physically aligned to this boundary.  Some cards cannot DMA across
- * a 4kB boundary.  With a standard Ethernet MTU, aligning to a 2kB
- * boundary is sufficient to guarantee no 4kB boundary crossings.  For
- * a jumbo Ethernet MTU, a packet may be larger than 4kB anyway.
- */
-#define PKBUFF_ALIGN 2048
-
-/**
- * Minimum packet buffer length
- *
- * alloc_pkb() will round up the allocated length to this size if
- * necessary.  This is used on behalf of hardware that is not capable
- * of auto-padding.
- */
-#define PKB_ZLEN 64
-
-/** A packet buffer
- *
- * This structure is used to represent a network packet within gPXE.
- */
-struct pk_buff {
-	/** List of which this buffer is a member */
-	struct list_head list;
-
-	/** Start of the buffer */
-	void *head;
-	/** Start of data */
-	void *data;
-	/** End of data */
-	void *tail;
-	/** End of the buffer */
-        void *end;
-};
-
-/**
- * Reserve space at start of packet buffer
- *
- * @v pkb	Packet buffer
- * @v len	Length to reserve
- * @ret data	Pointer to new start of buffer
- */
-static inline void * pkb_reserve ( struct pk_buff *pkb, size_t len ) {
-	pkb->data += len;
-	pkb->tail += len;
-	assert ( pkb->tail <= pkb->end );
-	return pkb->data;
-}
-
-/**
- * Add data to start of packet buffer
- *
- * @v pkb	Packet buffer
- * @v len	Length to add
- * @ret data	Pointer to new start of buffer
- */
-static inline void * pkb_push ( struct pk_buff *pkb, size_t len ) {
-	pkb->data -= len;
-	assert ( pkb->data >= pkb->head );
-	return pkb->data;
-}
-
-/**
- * Remove data from start of packet buffer
- *
- * @v pkb	Packet buffer
- * @v len	Length to remove
- * @ret data	Pointer to new start of buffer
- */
-static inline void * pkb_pull ( struct pk_buff *pkb, size_t len ) {
-	pkb->data += len;
-	assert ( pkb->data <= pkb->tail );
-	return pkb->data;
-}
-
-/**
- * Add data to end of packet buffer
- *
- * @v pkb	Packet buffer
- * @v len	Length to add
- * @ret data	Pointer to newly added space
- */
-static inline void * pkb_put ( struct pk_buff *pkb, size_t len ) {
-	void *old_tail = pkb->tail;
-	pkb->tail += len;
-	assert ( pkb->tail <= pkb->end );
-	return old_tail;
-}
-
-/**
- * Remove data from end of packet buffer
- *
- * @v pkb	Packet buffer
- * @v len	Length to remove
- */
-static inline void pkb_unput ( struct pk_buff *pkb, size_t len ) {
-	pkb->tail -= len;
-	assert ( pkb->tail >= pkb->data );
-}
-
-/**
- * Empty a packet buffer
- *
- * @v pkb	Packet buffer
- */
-static inline void pkb_empty ( struct pk_buff *pkb ) {
-	pkb->tail = pkb->data;
-}
-
-/**
- * Calculate length of data in a packet buffer
- *
- * @v pkb	Packet buffer
- * @ret len	Length of data in buffer
- */
-static inline size_t pkb_len ( struct pk_buff *pkb ) {
-	return ( pkb->tail - pkb->data );
-}
-
-/**
- * Calculate available space at start of a packet buffer
- *
- * @v pkb	Packet buffer
- * @ret len	Length of data available at start of buffer
- */
-static inline size_t pkb_headroom ( struct pk_buff *pkb ) {
-	return ( pkb->data - pkb->head );
-}
-
-/**
- * Calculate available space at end of a packet buffer
- *
- * @v pkb	Packet buffer
- * @ret len	Length of data available at end of buffer
- */
-static inline size_t pkb_tailroom ( struct pk_buff *pkb ) {
-	return ( pkb->end - pkb->tail );
-}
-
-extern struct pk_buff * alloc_pkb ( size_t len );
-extern void free_pkb ( struct pk_buff *pkb );
-extern void pkb_pad ( struct pk_buff *pkb, size_t min_len );
-
-#endif /* _GPXE_PKBUFF_H */
diff --git a/src/include/gpxe/tcp.h b/src/include/gpxe/tcp.h
index 576898e8..f16ca088 100644
--- a/src/include/gpxe/tcp.h
+++ b/src/include/gpxe/tcp.h
@@ -206,10 +206,10 @@ struct tcp_mss_option {
 /** Smallest port number on which a TCP connection can listen */
 #define TCP_MIN_PORT 1
 
-/* Some PKB constants */
+/* Some IOB constants */
 #define MAX_HDR_LEN	100
-#define MAX_PKB_LEN	1500
-#define MIN_PKB_LEN	MAX_HDR_LEN + 100 /* To account for padding by LL */
+#define MAX_IOB_LEN	1500
+#define MIN_IOB_LEN	MAX_HDR_LEN + 100 /* To account for padding by LL */
 
 /**
  * Maxmimum advertised TCP window size
diff --git a/src/include/gpxe/tcpip.h b/src/include/gpxe/tcpip.h
index ec708bc6..c0fadd23 100644
--- a/src/include/gpxe/tcpip.h
+++ b/src/include/gpxe/tcpip.h
@@ -12,7 +12,7 @@
 #include <gpxe/in.h>
 #include <gpxe/tables.h>
 
-struct pk_buff;
+struct io_buffer;
 struct net_device;
 
 /** Empty checksum value
@@ -51,15 +51,15 @@ struct tcpip_protocol {
        	/**
          * Process received packet
          *
-         * @v pkb		Packet buffer
+         * @v iobuf		I/O buffer
 	 * @v st_src		Partially-filled source address
 	 * @v st_dest		Partially-filled destination address
 	 * @v pshdr_csum	Pseudo-header checksum
 	 * @ret rc		Return status code
          *
-         * This method takes ownership of the packet buffer.
+         * This method takes ownership of the I/O buffer.
          */
-        int ( * rx ) ( struct pk_buff *pkb, struct sockaddr_tcpip *st_src,
+        int ( * rx ) ( struct io_buffer *iobuf, struct sockaddr_tcpip *st_src,
 		       struct sockaddr_tcpip *st_dest, uint16_t pshdr_csum );
         /** 
 	 * Transport-layer protocol number
@@ -80,16 +80,16 @@ struct tcpip_net_protocol {
 	/**
 	 * Transmit packet
 	 *
-	 * @v pkb		Packet buffer
+	 * @v iobuf		I/O buffer
 	 * @v tcpip_protocol	Transport-layer protocol
 	 * @v st_dest		Destination address
 	 * @v netdev		Network device (or NULL to route automatically)
 	 * @v trans_csum	Transport-layer checksum to complete, or NULL
 	 * @ret rc		Return status code
 	 *
-	 * This function takes ownership of the packet buffer.
+	 * This function takes ownership of the I/O buffer.
 	 */
-	int ( * tx ) ( struct pk_buff *pkb,
+	int ( * tx ) ( struct io_buffer *iobuf,
 		       struct tcpip_protocol *tcpip_protocol,
 		       struct sockaddr_tcpip *st_dest,
 		       struct net_device *netdev,
@@ -104,10 +104,10 @@ struct tcpip_net_protocol {
 #define	__tcpip_net_protocol \
 	__table ( struct tcpip_net_protocol, tcpip_net_protocols, 01 )
 
-extern int tcpip_rx ( struct pk_buff *pkb, uint8_t tcpip_proto,
+extern int tcpip_rx ( struct io_buffer *iobuf, uint8_t tcpip_proto,
 		      struct sockaddr_tcpip *st_src,
 		      struct sockaddr_tcpip *st_dest, uint16_t pshdr_csum );
-extern int tcpip_tx ( struct pk_buff *pkb, struct tcpip_protocol *tcpip, 
+extern int tcpip_tx ( struct io_buffer *iobuf, struct tcpip_protocol *tcpip, 
 		      struct sockaddr_tcpip *st_dest,
 		      struct net_device *netdev,
 		      uint16_t *trans_csum );
diff --git a/src/include/gpxe/udp.h b/src/include/gpxe/udp.h
index 074c5e1d..0ca77b4d 100644
--- a/src/include/gpxe/udp.h
+++ b/src/include/gpxe/udp.h
@@ -10,7 +10,7 @@
  */
 
 #include <stddef.h>
-#include <gpxe/pkbuff.h>
+#include <gpxe/iobuf.h>
 #include <gpxe/tcpip.h>
 #include <gpxe/if_ether.h>
 
@@ -21,8 +21,8 @@ struct net_device;
  */
 
 #define UDP_MAX_HLEN	72
-#define UDP_MAX_TXPKB	ETH_MAX_MTU
-#define UDP_MIN_TXPKB	ETH_ZLEN
+#define UDP_MAX_TXIOB	ETH_MAX_MTU
+#define UDP_MIN_TXIOB	ETH_ZLEN
 
 typedef uint16_t port_t;
 
@@ -86,7 +86,7 @@ struct udp_connection {
 	/** Local port on which the connection receives packets */
 	port_t local_port;
 	/** Transmit buffer */
-	struct pk_buff *tx_pkb;
+	struct io_buffer *tx_iob;
 	/** List of registered connections */
 	struct list_head list;
 	/** Operations table for this connection */
diff --git a/src/net/aoe.c b/src/net/aoe.c
index 58579e23..084a3d4d 100644
--- a/src/net/aoe.c
+++ b/src/net/aoe.c
@@ -25,7 +25,7 @@
 #include <gpxe/list.h>
 #include <gpxe/if_ether.h>
 #include <gpxe/ethernet.h>
-#include <gpxe/pkbuff.h>
+#include <gpxe/iobuf.h>
 #include <gpxe/uaccess.h>
 #include <gpxe/ata.h>
 #include <gpxe/netdevice.h>
@@ -70,7 +70,7 @@ static void aoe_done ( struct aoe_session *aoe, int rc ) {
  */
 static int aoe_send_command ( struct aoe_session *aoe ) {
 	struct ata_command *command = aoe->command;
-	struct pk_buff *pkb;
+	struct io_buffer *iobuf;
 	struct aoehdr *aoehdr;
 	struct aoecmd *aoecmd;
 	unsigned int count;
@@ -88,14 +88,14 @@ static int aoe_send_command ( struct aoe_session *aoe ) {
 		count = AOE_MAX_COUNT;
 	data_out_len = ( command->data_out ? ( count * ATA_SECTOR_SIZE ) : 0 );
 
-	/* Create outgoing packet buffer */
-	pkb = alloc_pkb ( ETH_HLEN + sizeof ( *aoehdr ) + sizeof ( *aoecmd ) +
+	/* Create outgoing I/O buffer */
+	iobuf = alloc_iob ( ETH_HLEN + sizeof ( *aoehdr ) + sizeof ( *aoecmd ) +
 			  data_out_len );
-	if ( ! pkb )
+	if ( ! iobuf )
 		return -ENOMEM;
-	pkb_reserve ( pkb, ETH_HLEN );
-	aoehdr = pkb_put ( pkb, sizeof ( *aoehdr ) );
-	aoecmd = pkb_put ( pkb, sizeof ( *aoecmd ) );
+	iob_reserve ( iobuf, ETH_HLEN );
+	aoehdr = iob_put ( iobuf, sizeof ( *aoehdr ) );
+	aoecmd = iob_put ( iobuf, sizeof ( *aoecmd ) );
 	memset ( aoehdr, 0, ( sizeof ( *aoehdr ) + sizeof ( *aoecmd ) ) );
 
 	/* Fill AoE header */
@@ -117,12 +117,12 @@ static int aoe_send_command ( struct aoe_session *aoe ) {
 		aoecmd->lba.bytes[3] |= ( command->cb.device & ATA_DEV_MASK );
 
 	/* Fill data payload */
-	copy_from_user ( pkb_put ( pkb, data_out_len ), command->data_out,
+	copy_from_user ( iob_put ( iobuf, data_out_len ), command->data_out,
 			 aoe->command_offset, data_out_len );
 
 	/* Send packet */
 	start_timer ( &aoe->timer );
-	return net_tx ( pkb, aoe->netdev, &aoe_protocol, aoe->target );
+	return net_tx ( iobuf, aoe->netdev, &aoe_protocol, aoe->target );
 }
 
 /**
@@ -213,16 +213,16 @@ static int aoe_rx_response ( struct aoe_session *aoe, struct aoehdr *aoehdr,
 /**
  * Process incoming AoE packets
  *
- * @v pkb		Packet buffer
+ * @v iobuf		I/O buffer
  * @v netdev		Network device
  * @v ll_source		Link-layer source address
  * @ret rc		Return status code
  *
  */
-static int aoe_rx ( struct pk_buff *pkb, struct net_device *netdev __unused,
+static int aoe_rx ( struct io_buffer *iobuf, struct net_device *netdev __unused,
 		    const void *ll_source ) {
-	struct aoehdr *aoehdr = pkb->data;
-	unsigned int len = pkb_len ( pkb );
+	struct aoehdr *aoehdr = iobuf->data;
+	unsigned int len = iob_len ( iobuf );
 	struct aoe_session *aoe;
 	int rc = 0;
 
@@ -254,7 +254,7 @@ static int aoe_rx ( struct pk_buff *pkb, struct net_device *netdev __unused,
 	}
 
  done:
-	free_pkb ( pkb );
+	free_iob ( iobuf );
 	return rc;
 }
 
diff --git a/src/net/arp.c b/src/net/arp.c
index 897906bc..383dc842 100644
--- a/src/net/arp.c
+++ b/src/net/arp.c
@@ -22,7 +22,7 @@
 #include <errno.h>
 #include <gpxe/if_ether.h>
 #include <gpxe/if_arp.h>
-#include <gpxe/pkbuff.h>
+#include <gpxe/iobuf.h>
 #include <gpxe/netdevice.h>
 #include <gpxe/arp.h>
 
@@ -119,7 +119,7 @@ int arp_resolve ( struct net_device *netdev, struct net_protocol *net_protocol,
 		  void *dest_ll_addr ) {
 	struct ll_protocol *ll_protocol = netdev->ll_protocol;
 	const struct arp_entry *arp;
-	struct pk_buff *pkb;
+	struct io_buffer *iobuf;
 	struct arphdr *arphdr;
 	int rc;
 
@@ -136,30 +136,30 @@ int arp_resolve ( struct net_device *netdev, struct net_protocol *net_protocol,
 	      net_protocol->ntoa ( dest_net_addr ) );
 
 	/* Allocate ARP packet */
-	pkb = alloc_pkb ( MAX_LL_HEADER_LEN + sizeof ( *arphdr ) +
+	iobuf = alloc_iob ( MAX_LL_HEADER_LEN + sizeof ( *arphdr ) +
 			  2 * ( MAX_LL_ADDR_LEN + MAX_NET_ADDR_LEN ) );
-	if ( ! pkb )
+	if ( ! iobuf )
 		return -ENOMEM;
-	pkb_reserve ( pkb, MAX_LL_HEADER_LEN );
+	iob_reserve ( iobuf, MAX_LL_HEADER_LEN );
 
 	/* Build up ARP request */
-	arphdr = pkb_put ( pkb, sizeof ( *arphdr ) );
+	arphdr = iob_put ( iobuf, sizeof ( *arphdr ) );
 	arphdr->ar_hrd = ll_protocol->ll_proto;
 	arphdr->ar_hln = ll_protocol->ll_addr_len;
 	arphdr->ar_pro = net_protocol->net_proto;
 	arphdr->ar_pln = net_protocol->net_addr_len;
 	arphdr->ar_op = htons ( ARPOP_REQUEST );
-	memcpy ( pkb_put ( pkb, ll_protocol->ll_addr_len ),
+	memcpy ( iob_put ( iobuf, ll_protocol->ll_addr_len ),
 		 netdev->ll_addr, ll_protocol->ll_addr_len );
-	memcpy ( pkb_put ( pkb, net_protocol->net_addr_len ),
+	memcpy ( iob_put ( iobuf, net_protocol->net_addr_len ),
 		 source_net_addr, net_protocol->net_addr_len );
-	memset ( pkb_put ( pkb, ll_protocol->ll_addr_len ),
+	memset ( iob_put ( iobuf, ll_protocol->ll_addr_len ),
 		 0, ll_protocol->ll_addr_len );
-	memcpy ( pkb_put ( pkb, net_protocol->net_addr_len ),
+	memcpy ( iob_put ( iobuf, net_protocol->net_addr_len ),
 		 dest_net_addr, net_protocol->net_addr_len );
 
 	/* Transmit ARP request */
-	if ( ( rc = net_tx ( pkb, netdev, &arp_protocol, 
+	if ( ( rc = net_tx ( iobuf, netdev, &arp_protocol, 
 			     ll_protocol->ll_broadcast ) ) != 0 )
 		return rc;
 
@@ -188,7 +188,7 @@ static struct arp_net_protocol * arp_find_protocol ( uint16_t net_proto ) {
 /**
  * Process incoming ARP packets
  *
- * @v pkb		Packet buffer
+ * @v iobuf		I/O buffer
  * @v netdev		Network device
  * @v ll_source		Link-layer source address
  * @ret rc		Return status code
@@ -199,9 +199,9 @@ static struct arp_net_protocol * arp_find_protocol ( uint16_t net_proto ) {
  * avoiding the need for extraneous ARP requests; read the RFC for
  * details.
  */
-static int arp_rx ( struct pk_buff *pkb, struct net_device *netdev,
+static int arp_rx ( struct io_buffer *iobuf, struct net_device *netdev,
 		    const void *ll_source __unused ) {
-	struct arphdr *arphdr = pkb->data;
+	struct arphdr *arphdr = iobuf->data;
 	struct arp_net_protocol *arp_net_protocol;
 	struct net_protocol *net_protocol;
 	struct ll_protocol *ll_protocol;
@@ -265,11 +265,11 @@ static int arp_rx ( struct pk_buff *pkb, struct net_device *netdev,
 	memcpy ( arp_sender_ha ( arphdr ), netdev->ll_addr, arphdr->ar_hln );
 
 	/* Send reply */
-	net_tx ( pkb, netdev, &arp_protocol, arp_target_ha (arphdr ) );
-	pkb = NULL;
+	net_tx ( iobuf, netdev, &arp_protocol, arp_target_ha (arphdr ) );
+	iobuf = NULL;
 
  done:
-	free_pkb ( pkb );
+	free_iob ( iobuf );
 	return 0;
 }
 
diff --git a/src/net/ethernet.c b/src/net/ethernet.c
index cee67d46..7108beff 100644
--- a/src/net/ethernet.c
+++ b/src/net/ethernet.c
@@ -25,7 +25,7 @@
 #include <gpxe/if_arp.h>
 #include <gpxe/if_ether.h>
 #include <gpxe/netdevice.h>
-#include <gpxe/pkbuff.h>
+#include <gpxe/iobuf.h>
 #include <gpxe/ethernet.h>
 
 /** @file
@@ -40,16 +40,16 @@ static uint8_t eth_broadcast[ETH_ALEN] = { 0xff, 0xff, 0xff, 0xff, 0xff, 0xff};
 /**
  * Transmit Ethernet packet
  *
- * @v pkb		Packet buffer
+ * @v iobuf		I/O buffer
  * @v netdev		Network device
  * @v net_protocol	Network-layer protocol
  * @v ll_dest		Link-layer destination address
  *
  * Prepends the Ethernet link-layer header and transmits the packet.
  */
-static int eth_tx ( struct pk_buff *pkb, struct net_device *netdev,
+static int eth_tx ( struct io_buffer *iobuf, struct net_device *netdev,
 		    struct net_protocol *net_protocol, const void *ll_dest ) {
-	struct ethhdr *ethhdr = pkb_push ( pkb, sizeof ( *ethhdr ) );
+	struct ethhdr *ethhdr = iob_push ( iobuf, sizeof ( *ethhdr ) );
 
 	/* Build Ethernet header */
 	memcpy ( ethhdr->h_dest, ll_dest, ETH_ALEN );
@@ -57,34 +57,34 @@ static int eth_tx ( struct pk_buff *pkb, struct net_device *netdev,
 	ethhdr->h_protocol = net_protocol->net_proto;
 
 	/* Hand off to network device */
-	return netdev_tx ( netdev, pkb );
+	return netdev_tx ( netdev, iobuf );
 }
 
 /**
  * Process received Ethernet packet
  *
- * @v pkb	Packet buffer
+ * @v iobuf	I/O buffer
  * @v netdev	Network device
  *
  * Strips off the Ethernet link-layer header and passes up to the
  * network-layer protocol.
  */
-static int eth_rx ( struct pk_buff *pkb, struct net_device *netdev ) {
-	struct ethhdr *ethhdr = pkb->data;
+static int eth_rx ( struct io_buffer *iobuf, struct net_device *netdev ) {
+	struct ethhdr *ethhdr = iobuf->data;
 
 	/* Sanity check */
-	if ( pkb_len ( pkb ) < sizeof ( *ethhdr ) ) {
+	if ( iob_len ( iobuf ) < sizeof ( *ethhdr ) ) {
 		DBG ( "Ethernet packet too short (%d bytes)\n",
-		      pkb_len ( pkb ) );
-		free_pkb ( pkb );
+		      iob_len ( iobuf ) );
+		free_iob ( iobuf );
 		return -EINVAL;
 	}
 
 	/* Strip off Ethernet header */
-	pkb_pull ( pkb, sizeof ( *ethhdr ) );
+	iob_pull ( iobuf, sizeof ( *ethhdr ) );
 
 	/* Hand off to network-layer protocol */
-	return net_rx ( pkb, netdev, ethhdr->h_protocol, ethhdr->h_source );
+	return net_rx ( iobuf, netdev, ethhdr->h_protocol, ethhdr->h_source );
 }
 
 /**
diff --git a/src/net/icmpv6.c b/src/net/icmpv6.c
index 4eed0584..da738923 100644
--- a/src/net/icmpv6.c
+++ b/src/net/icmpv6.c
@@ -5,7 +5,7 @@
 #include <gpxe/in.h>
 #include <gpxe/ip6.h>
 #include <gpxe/if_ether.h>
-#include <gpxe/pkbuff.h>
+#include <gpxe/iobuf.h>
 #include <gpxe/ndp.h>
 #include <gpxe/icmp6.h>
 #include <gpxe/tcpip.h>
@@ -31,9 +31,9 @@ int icmp6_send_solicit ( struct net_device *netdev, struct in6_addr *src __unuse
 	} st_dest;
 	struct ll_protocol *ll_protocol = netdev->ll_protocol;
 	struct neighbour_solicit *nsolicit;
-	struct pk_buff *pkb = alloc_pkb ( sizeof ( *nsolicit ) + MIN_PKB_LEN );
-	pkb_reserve ( pkb, MAX_HDR_LEN );
-	nsolicit = pkb_put ( pkb, sizeof ( *nsolicit ) );
+	struct io_buffer *iobuf = alloc_iob ( sizeof ( *nsolicit ) + MIN_IOB_LEN );
+	iob_reserve ( iobuf, MAX_HDR_LEN );
+	nsolicit = iob_put ( iobuf, sizeof ( *nsolicit ) );
 
 	/* Fill up the headers */
 	memset ( nsolicit, 0, sizeof ( *nsolicit ) );
@@ -60,25 +60,25 @@ int icmp6_send_solicit ( struct net_device *netdev, struct in6_addr *src __unuse
 	st_dest.sin6.sin6_addr.in6_u.u6_addr8[13] = 0xff;
 	
 	/* Send packet over IP6 */
-	return tcpip_tx ( pkb, &icmp6_protocol, &st_dest.st,
+	return tcpip_tx ( iobuf, &icmp6_protocol, &st_dest.st,
 			  NULL, &nsolicit->csum );
 }
 
 /**
  * Process ICMP6 headers
  *
- * @v pkb	Packet buffer
+ * @v iobuf	I/O buffer
  * @v st_src	Source address
  * @v st_dest	Destination address
  */
-static int icmp6_rx ( struct pk_buff *pkb, struct sockaddr_tcpip *st_src,
+static int icmp6_rx ( struct io_buffer *iobuf, struct sockaddr_tcpip *st_src,
 		      struct sockaddr_tcpip *st_dest ) {
-	struct icmp6_header *icmp6hdr = pkb->data;
+	struct icmp6_header *icmp6hdr = iobuf->data;
 
 	/* Sanity check */
-	if ( pkb_len ( pkb ) < sizeof ( *icmp6hdr ) ) {
-		DBG ( "Packet too short (%d bytes)\n", pkb_len ( pkb ) );
-		free_pkb ( pkb );
+	if ( iob_len ( iobuf ) < sizeof ( *icmp6hdr ) ) {
+		DBG ( "Packet too short (%d bytes)\n", iob_len ( iobuf ) );
+		free_iob ( iobuf );
 		return -EINVAL;
 	}
 
@@ -87,7 +87,7 @@ static int icmp6_rx ( struct pk_buff *pkb, struct sockaddr_tcpip *st_src,
 	/* Process the ICMP header */
 	switch ( icmp6hdr->type ) {
 	case ICMP6_NADVERT:
-		return ndp_process_advert ( pkb, st_src, st_dest );
+		return ndp_process_advert ( iobuf, st_src, st_dest );
 	}
 	return -ENOSYS;
 }
@@ -97,9 +97,9 @@ void icmp6_test_nadvert (struct net_device *netdev, struct sockaddr_in6 *server_
 
 		struct sockaddr_in6 server;
 		memcpy ( &server, server_p, sizeof ( server ) );
-                struct pk_buff *rxpkb = alloc_pkb ( 500 );
-                pkb_reserve ( rxpkb, MAX_HDR_LEN );
-                struct neighbour_advert *nadvert = pkb_put ( rxpkb, sizeof ( *nadvert ) );
+                struct io_buffer *rxiobuf = alloc_iob ( 500 );
+                iob_reserve ( rxiobuf, MAX_HDR_LEN );
+                struct neighbour_advert *nadvert = iob_put ( rxiobuf, sizeof ( *nadvert ) );
                 nadvert->type = 136;
                 nadvert->code = 0;
                 nadvert->flags = ICMP6_FLAGS_SOLICITED;
@@ -108,15 +108,15 @@ void icmp6_test_nadvert (struct net_device *netdev, struct sockaddr_in6 *server_
                 nadvert->opt_type = 2;
                 nadvert->opt_len = 1;
                 memcpy ( nadvert->opt_ll_addr, ll_addr, 6 );
-                struct ip6_header *ip6hdr = pkb_push ( rxpkb, sizeof ( *ip6hdr ) );
+                struct ip6_header *ip6hdr = iob_push ( rxiobuf, sizeof ( *ip6hdr ) );
                 ip6hdr->ver_traffic_class_flow_label = htonl ( 0x60000000 );
 		ip6hdr->hop_limit = 255;
 		ip6hdr->nxt_hdr = 58;
 		ip6hdr->payload_len = htons ( sizeof ( *nadvert ) );
                 ip6hdr->src = server.sin6_addr;
                 ip6hdr->dest = server.sin6_addr;
-		hex_dump ( rxpkb->data, pkb_len ( rxpkb ) );
-                net_rx ( rxpkb, netdev, htons ( ETH_P_IPV6 ), ll_addr );
+		hex_dump ( rxiobuf->data, iob_len ( rxiobuf ) );
+                net_rx ( rxiobuf, netdev, htons ( ETH_P_IPV6 ), ll_addr );
 }
 #endif
 
diff --git a/src/net/ipv4.c b/src/net/ipv4.c
index 8bbcff15..a6fb65ed 100644
--- a/src/net/ipv4.c
+++ b/src/net/ipv4.c
@@ -8,7 +8,7 @@
 #include <gpxe/in.h>
 #include <gpxe/arp.h>
 #include <gpxe/if_ether.h>
-#include <gpxe/pkbuff.h>
+#include <gpxe/iobuf.h>
 #include <gpxe/netdevice.h>
 #include <gpxe/ip.h>
 #include <gpxe/tcpip.h>
@@ -205,11 +205,11 @@ static void free_fragbuf ( struct frag_buffer *fragbuf ) {
 /**
  * Fragment reassembler
  *
- * @v pkb		Packet buffer, fragment of the datagram
- * @ret frag_pkb	Reassembled packet, or NULL
+ * @v iobuf		I/O buffer, fragment of the datagram
+ * @ret frag_iob	Reassembled packet, or NULL
  */
-static struct pk_buff * ipv4_reassemble ( struct pk_buff * pkb ) {
-	struct iphdr *iphdr = pkb->data;
+static struct io_buffer * ipv4_reassemble ( struct io_buffer * iobuf ) {
+	struct iphdr *iphdr = iobuf->data;
 	struct frag_buffer *fragbuf;
 	
 	/**
@@ -223,31 +223,31 @@ static struct pk_buff * ipv4_reassemble ( struct pk_buff * pkb ) {
 			 * 
 			 * The offset of the new packet must be equal to the
 			 * length of the data accumulated so far (the length of
-			 * the reassembled packet buffer
+			 * the reassembled I/O buffer
 			 */
-			if ( pkb_len ( fragbuf->frag_pkb ) == 
+			if ( iob_len ( fragbuf->frag_iob ) == 
 			      ( iphdr->frags & IP_MASK_OFFSET ) ) {
 				/**
 				 * Append the contents of the fragment to the
-				 * reassembled packet buffer
+				 * reassembled I/O buffer
 				 */
-				pkb_pull ( pkb, sizeof ( *iphdr ) );
-				memcpy ( pkb_put ( fragbuf->frag_pkb,
-							pkb_len ( pkb ) ),
-					 pkb->data, pkb_len ( pkb ) );
-				free_pkb ( pkb );
+				iob_pull ( iobuf, sizeof ( *iphdr ) );
+				memcpy ( iob_put ( fragbuf->frag_iob,
+							iob_len ( iobuf ) ),
+					 iobuf->data, iob_len ( iobuf ) );
+				free_iob ( iobuf );
 
 				/** Check if the fragment series is over */
 				if ( !iphdr->frags & IP_MASK_MOREFRAGS ) {
-					pkb = fragbuf->frag_pkb;
+					iobuf = fragbuf->frag_iob;
 					free_fragbuf ( fragbuf );
-					return pkb;
+					return iobuf;
 				}
 
 			} else {
 				/* Discard the fragment series */
 				free_fragbuf ( fragbuf );
-				free_pkb ( pkb );
+				free_iob ( iobuf );
 			}
 			return NULL;
 		}
@@ -262,12 +262,12 @@ static struct pk_buff * ipv4_reassemble ( struct pk_buff * pkb ) {
 		fragbuf->ident = iphdr->ident;
 		fragbuf->src = iphdr->src;
 
-		/* Set up the reassembly packet buffer */
-		fragbuf->frag_pkb = alloc_pkb ( IP_FRAG_PKB_SIZE );
-		pkb_pull ( pkb, sizeof ( *iphdr ) );
-		memcpy ( pkb_put ( fragbuf->frag_pkb, pkb_len ( pkb ) ),
-			 pkb->data, pkb_len ( pkb ) );
-		free_pkb ( pkb );
+		/* Set up the reassembly I/O buffer */
+		fragbuf->frag_iob = alloc_iob ( IP_FRAG_IOB_SIZE );
+		iob_pull ( iobuf, sizeof ( *iphdr ) );
+		memcpy ( iob_put ( fragbuf->frag_iob, iob_len ( iobuf ) ),
+			 iobuf->data, iob_len ( iobuf ) );
+		free_iob ( iobuf );
 
 		/* Set the reassembly timer */
 		fragbuf->frag_timer.timeout = IP_FRAG_TIMEOUT;
@@ -284,13 +284,13 @@ static struct pk_buff * ipv4_reassemble ( struct pk_buff * pkb ) {
 /**
  * Add IPv4 pseudo-header checksum to existing checksum
  *
- * @v pkb		Packet buffer
+ * @v iobuf		I/O buffer
  * @v csum		Existing checksum
  * @ret csum		Updated checksum
  */
-static uint16_t ipv4_pshdr_chksum ( struct pk_buff *pkb, uint16_t csum ) {
+static uint16_t ipv4_pshdr_chksum ( struct io_buffer *iobuf, uint16_t csum ) {
 	struct ipv4_pseudo_header pshdr;
-	struct iphdr *iphdr = pkb->data;
+	struct iphdr *iphdr = iobuf->data;
 	size_t hdrlen = ( ( iphdr->verhdrlen & IP_MASK_HLEN ) * 4 );
 
 	/* Build pseudo-header */
@@ -298,7 +298,7 @@ static uint16_t ipv4_pshdr_chksum ( struct pk_buff *pkb, uint16_t csum ) {
 	pshdr.dest = iphdr->dest;
 	pshdr.zero_padding = 0x00;
 	pshdr.protocol = iphdr->protocol;
-	pshdr.len = htons ( pkb_len ( pkb ) - hdrlen );
+	pshdr.len = htons ( iob_len ( iobuf ) - hdrlen );
 
 	/* Update the checksum value */
 	return tcpip_continue_chksum ( csum, &pshdr, sizeof ( pshdr ) );
@@ -345,7 +345,7 @@ static int ipv4_ll_addr ( struct in_addr dest, struct in_addr src,
 /**
  * Transmit IP packet
  *
- * @v pkb		Packet buffer
+ * @v iobuf		I/O buffer
  * @v tcpip		Transport-layer protocol
  * @v st_dest		Destination network-layer address
  * @v netdev		Network device to use if no route found, or NULL
@@ -354,12 +354,12 @@ static int ipv4_ll_addr ( struct in_addr dest, struct in_addr src,
  *
  * This function expects a transport-layer segment and prepends the IP header
  */
-static int ipv4_tx ( struct pk_buff *pkb,
+static int ipv4_tx ( struct io_buffer *iobuf,
 		     struct tcpip_protocol *tcpip_protocol,
 		     struct sockaddr_tcpip *st_dest,
 		     struct net_device *netdev,
 		     uint16_t *trans_csum ) {
-	struct iphdr *iphdr = pkb_push ( pkb, sizeof ( *iphdr ) );
+	struct iphdr *iphdr = iob_push ( iobuf, sizeof ( *iphdr ) );
 	struct sockaddr_in *sin_dest = ( ( struct sockaddr_in * ) st_dest );
 	struct ipv4_miniroute *miniroute;
 	struct in_addr next_hop;
@@ -370,7 +370,7 @@ static int ipv4_tx ( struct pk_buff *pkb,
 	memset ( iphdr, 0, sizeof ( *iphdr ) );
 	iphdr->verhdrlen = ( IP_VER | ( sizeof ( *iphdr ) / 4 ) );
 	iphdr->service = IP_TOS;
-	iphdr->len = htons ( pkb_len ( pkb ) );	
+	iphdr->len = htons ( iob_len ( iobuf ) );	
 	iphdr->ident = htons ( ++next_ident );
 	iphdr->ttl = IP_TTL;
 	iphdr->protocol = tcpip_protocol->tcpip_proto;
@@ -398,7 +398,7 @@ static int ipv4_tx ( struct pk_buff *pkb,
 
 	/* Fix up checksums */
 	if ( trans_csum )
-		*trans_csum = ipv4_pshdr_chksum ( pkb, *trans_csum );
+		*trans_csum = ipv4_pshdr_chksum ( iobuf, *trans_csum );
 	iphdr->chksum = tcpip_chksum ( iphdr, sizeof ( *iphdr ) );
 
 	/* Print IP4 header for debugging */
@@ -408,7 +408,7 @@ static int ipv4_tx ( struct pk_buff *pkb,
 	      ntohs ( iphdr->ident ), ntohs ( iphdr->chksum ) );
 
 	/* Hand off to link layer */
-	if ( ( rc = net_tx ( pkb, netdev, &ipv4_protocol, ll_dest ) ) != 0 ) {
+	if ( ( rc = net_tx ( iobuf, netdev, &ipv4_protocol, ll_dest ) ) != 0 ) {
 		DBG ( "IPv4 could not transmit packet via %s: %s\n",
 		      netdev->name, strerror ( rc ) );
 		return rc;
@@ -417,23 +417,23 @@ static int ipv4_tx ( struct pk_buff *pkb,
 	return 0;
 
  err:
-	free_pkb ( pkb );
+	free_iob ( iobuf );
 	return rc;
 }
 
 /**
  * Process incoming packets
  *
- * @v pkb	Packet buffer
+ * @v iobuf	I/O buffer
  * @v netdev	Network device
  * @v ll_source	Link-layer destination source
  *
  * This function expects an IP4 network datagram. It processes the headers 
  * and sends it to the transport layer.
  */
-static int ipv4_rx ( struct pk_buff *pkb, struct net_device *netdev __unused,
+static int ipv4_rx ( struct io_buffer *iobuf, struct net_device *netdev __unused,
 		     const void *ll_source __unused ) {
-	struct iphdr *iphdr = pkb->data;
+	struct iphdr *iphdr = iobuf->data;
 	size_t hdrlen;
 	size_t len;
 	union {
@@ -445,9 +445,9 @@ static int ipv4_rx ( struct pk_buff *pkb, struct net_device *netdev __unused,
 	int rc;
 
 	/* Sanity check the IPv4 header */
-	if ( pkb_len ( pkb ) < sizeof ( *iphdr ) ) {
+	if ( iob_len ( iobuf ) < sizeof ( *iphdr ) ) {
 		DBG ( "IPv4 packet too short at %d bytes (min %d bytes)\n",
-		      pkb_len ( pkb ), sizeof ( *iphdr ) );
+		      iob_len ( iobuf ), sizeof ( *iphdr ) );
 		goto err;
 	}
 	if ( ( iphdr->verhdrlen & IP_MASK_VER ) != IP_VER ) {
@@ -460,9 +460,9 @@ static int ipv4_rx ( struct pk_buff *pkb, struct net_device *netdev __unused,
 		      hdrlen, sizeof ( *iphdr ) );
 		goto err;
 	}
-	if ( hdrlen > pkb_len ( pkb ) ) {
+	if ( hdrlen > iob_len ( iobuf ) ) {
 		DBG ( "IPv4 header too long at %d bytes "
-		      "(packet is %d bytes)\n", hdrlen, pkb_len ( pkb ) );
+		      "(packet is %d bytes)\n", hdrlen, iob_len ( iobuf ) );
 		goto err;
 	}
 	if ( ( csum = tcpip_chksum ( iphdr, hdrlen ) ) != 0 ) {
@@ -476,9 +476,9 @@ static int ipv4_rx ( struct pk_buff *pkb, struct net_device *netdev __unused,
 		      "(header is %d bytes)\n", len, hdrlen );
 		goto err;
 	}
-	if ( len > pkb_len ( pkb ) ) {
+	if ( len > iob_len ( iobuf ) ) {
 		DBG ( "IPv4 length too long at %d bytes "
-		      "(packet is %d bytes)\n", len, pkb_len ( pkb ) );
+		      "(packet is %d bytes)\n", len, iob_len ( iobuf ) );
 		goto err;
 	}
 
@@ -491,18 +491,18 @@ static int ipv4_rx ( struct pk_buff *pkb, struct net_device *netdev __unused,
 	/* Truncate packet to correct length, calculate pseudo-header
 	 * checksum and then strip off the IPv4 header.
 	 */
-	pkb_unput ( pkb, ( pkb_len ( pkb ) - len ) );
-	pshdr_csum = ipv4_pshdr_chksum ( pkb, TCPIP_EMPTY_CSUM );
-	pkb_pull ( pkb, hdrlen );
+	iob_unput ( iobuf, ( iob_len ( iobuf ) - len ) );
+	pshdr_csum = ipv4_pshdr_chksum ( iobuf, TCPIP_EMPTY_CSUM );
+	iob_pull ( iobuf, hdrlen );
 
 	/* Fragment reassembly */
 	if ( ( iphdr->frags & htons ( IP_MASK_MOREFRAGS ) ) || 
 	     ( ( iphdr->frags & htons ( IP_MASK_OFFSET ) ) != 0 ) ) {
 		/* Pass the fragment to ipv4_reassemble() which either
-		 * returns a fully reassembled packet buffer or NULL.
+		 * returns a fully reassembled I/O buffer or NULL.
 		 */
-		pkb = ipv4_reassemble ( pkb );
-		if ( ! pkb )
+		iobuf = ipv4_reassemble ( iobuf );
+		if ( ! iobuf )
 			return 0;
 	}
 
@@ -513,7 +513,7 @@ static int ipv4_rx ( struct pk_buff *pkb, struct net_device *netdev __unused,
 	memset ( &dest, 0, sizeof ( dest ) );
 	dest.sin.sin_family = AF_INET;
 	dest.sin.sin_addr = iphdr->dest;
-	if ( ( rc = tcpip_rx ( pkb, iphdr->protocol, &src.st,
+	if ( ( rc = tcpip_rx ( iobuf, iphdr->protocol, &src.st,
 			       &dest.st, pshdr_csum ) ) != 0 ) {
 		DBG ( "IPv4 received packet rejected by stack: %s\n",
 		      strerror ( rc ) );
@@ -523,7 +523,7 @@ static int ipv4_rx ( struct pk_buff *pkb, struct net_device *netdev __unused,
 	return 0;
 
  err:
-	free_pkb ( pkb );
+	free_iob ( iobuf );
 	return -EINVAL;
 }
 
diff --git a/src/net/ipv6.c b/src/net/ipv6.c
index 458a9375..98e1631d 100644
--- a/src/net/ipv6.c
+++ b/src/net/ipv6.c
@@ -11,7 +11,7 @@
 #include <gpxe/icmp6.h>
 #include <gpxe/tcpip.h>
 #include <gpxe/socket.h>
-#include <gpxe/pkbuff.h>
+#include <gpxe/iobuf.h>
 #include <gpxe/netdevice.h>
 #include <gpxe/if_ether.h>
 
@@ -157,21 +157,21 @@ void del_ipv6_address ( struct net_device *netdev ) {
 /**
  * Calculate TCPIP checksum
  *
- * @v pkb	Packet buffer
+ * @v iobuf	I/O buffer
  * @v tcpip	TCP/IP protocol
  *
  * This function constructs the pseudo header and completes the checksum in the
  * upper layer header.
  */
-static uint16_t ipv6_tx_csum ( struct pk_buff *pkb, uint16_t csum ) {
-	struct ip6_header *ip6hdr = pkb->data;
+static uint16_t ipv6_tx_csum ( struct io_buffer *iobuf, uint16_t csum ) {
+	struct ip6_header *ip6hdr = iobuf->data;
 	struct ipv6_pseudo_header pshdr;
 
 	/* Calculate pseudo header */
 	memset ( &pshdr, 0, sizeof ( pshdr ) );
 	pshdr.src = ip6hdr->src;
 	pshdr.dest = ip6hdr->dest;
-	pshdr.len = htons ( pkb_len ( pkb ) - sizeof ( *ip6hdr ) );
+	pshdr.len = htons ( iob_len ( iobuf ) - sizeof ( *ip6hdr ) );
 	pshdr.nxt_hdr = ip6hdr->nxt_hdr;
 
 	/* Update checksum value */
@@ -192,13 +192,13 @@ void ipv6_dump ( struct ip6_header *ip6hdr ) {
 /**
  * Transmit IP6 packet
  *
- * pkb		Packet buffer
+ * iobuf		I/O buffer
  * tcpip	TCP/IP protocol
  * st_dest	Destination socket address
  *
  * This function prepends the IPv6 headers to the payload an transmits it.
  */
-static int ipv6_tx ( struct pk_buff *pkb,
+static int ipv6_tx ( struct io_buffer *iobuf,
 		     struct tcpip_protocol *tcpip,
 		     struct sockaddr_tcpip *st_dest,
 		     struct net_device *netdev,
@@ -211,10 +211,10 @@ static int ipv6_tx ( struct pk_buff *pkb,
 	int rc;
 
 	/* Construct the IPv6 packet */
-	struct ip6_header *ip6hdr = pkb_push ( pkb, sizeof ( *ip6hdr ) );
+	struct ip6_header *ip6hdr = iob_push ( iobuf, sizeof ( *ip6hdr ) );
 	memset ( ip6hdr, 0, sizeof ( *ip6hdr) );
 	ip6hdr->ver_traffic_class_flow_label = htonl ( 0x60000000 );//IP6_VERSION;
-	ip6hdr->payload_len = htons ( pkb_len ( pkb ) - sizeof ( *ip6hdr ) );
+	ip6hdr->payload_len = htons ( iob_len ( iobuf ) - sizeof ( *ip6hdr ) );
 	ip6hdr->nxt_hdr = tcpip->tcpip_proto;
 	ip6hdr->hop_limit = IP6_HOP_LIMIT; // 255
 
@@ -244,7 +244,7 @@ static int ipv6_tx ( struct pk_buff *pkb,
 
 	/* Complete the transport layer checksum */
 	if ( trans_csum )
-		*trans_csum = ipv6_tx_csum ( pkb, *trans_csum );
+		*trans_csum = ipv6_tx_csum ( iobuf, *trans_csum );
 
 	/* Print IPv6 header */
 	ipv6_dump ( ip6hdr );
@@ -267,24 +267,24 @@ static int ipv6_tx ( struct pk_buff *pkb,
 	}
 
 	/* Transmit packet */
-	return net_tx ( pkb, netdev, &ipv6_protocol, ll_dest );
+	return net_tx ( iobuf, netdev, &ipv6_protocol, ll_dest );
 
   err:
-	free_pkb ( pkb );
+	free_iob ( iobuf );
 	return rc;
 }
 
 /**
  * Process next IP6 header
  *
- * @v pkb	Packet buffer
+ * @v iobuf	I/O buffer
  * @v nxt_hdr	Next header number
  * @v src	Source socket address
  * @v dest	Destination socket address
  *
  * Refer http://www.iana.org/assignments/ipv6-parameters for the numbers
  */
-static int ipv6_process_nxt_hdr ( struct pk_buff *pkb, uint8_t nxt_hdr,
+static int ipv6_process_nxt_hdr ( struct io_buffer *iobuf, uint8_t nxt_hdr,
 		struct sockaddr_tcpip *src, struct sockaddr_tcpip *dest ) {
 	switch ( nxt_hdr ) {
 	case IP6_HOPBYHOP: 
@@ -302,31 +302,31 @@ static int ipv6_process_nxt_hdr ( struct pk_buff *pkb, uint8_t nxt_hdr,
 		return 0;
 	}
 	/* Next header is not a IPv6 extension header */
-	return tcpip_rx ( pkb, nxt_hdr, src, dest, 0 /* fixme */ );
+	return tcpip_rx ( iobuf, nxt_hdr, src, dest, 0 /* fixme */ );
 }
 
 /**
  * Process incoming IP6 packets
  *
- * @v pkb		Packet buffer
+ * @v iobuf		I/O buffer
  * @v netdev		Network device
  * @v ll_source		Link-layer source address
  *
  * This function processes a IPv6 packet
  */
-static int ipv6_rx ( struct pk_buff *pkb,
+static int ipv6_rx ( struct io_buffer *iobuf,
 		     struct net_device *netdev,
 		     const void *ll_source ) {
 
-	struct ip6_header *ip6hdr = pkb->data;
+	struct ip6_header *ip6hdr = iobuf->data;
 	union {
 		struct sockaddr_in6 sin6;
 		struct sockaddr_tcpip st;
 	} src, dest;
 
 	/* Sanity check */
-	if ( pkb_len ( pkb ) < sizeof ( *ip6hdr ) ) {
-		DBG ( "Packet too short (%d bytes)\n", pkb_len ( pkb ) );
+	if ( iob_len ( iobuf ) < sizeof ( *ip6hdr ) ) {
+		DBG ( "Packet too short (%d bytes)\n", iob_len ( iobuf ) );
 		goto drop;
 	}
 
@@ -342,7 +342,7 @@ static int ipv6_rx ( struct pk_buff *pkb,
 	}
 
 	/* Check the payload length */
-	if ( ntohs ( ip6hdr->payload_len ) > pkb_len ( pkb ) ) {
+	if ( ntohs ( ip6hdr->payload_len ) > iob_len ( iobuf ) ) {
 		DBG ( "Inconsistent packet length (%d bytes)\n",
 			ip6hdr->payload_len );
 		goto drop;
@@ -359,16 +359,16 @@ static int ipv6_rx ( struct pk_buff *pkb,
 	dest.sin6.sin6_addr = ip6hdr->dest;
 
 	/* Strip header */
-	pkb_unput ( pkb, pkb_len ( pkb ) - ntohs ( ip6hdr->payload_len ) -
+	iob_unput ( iobuf, iob_len ( iobuf ) - ntohs ( ip6hdr->payload_len ) -
 							sizeof ( *ip6hdr ) );
-	pkb_pull ( pkb, sizeof ( *ip6hdr ) );
+	iob_pull ( iobuf, sizeof ( *ip6hdr ) );
 
 	/* Send it to the transport layer */
-	return ipv6_process_nxt_hdr ( pkb, ip6hdr->nxt_hdr, &src.st, &dest.st );
+	return ipv6_process_nxt_hdr ( iobuf, ip6hdr->nxt_hdr, &src.st, &dest.st );
 
   drop:
 	DBG ( "Packet dropped\n" );
-	free_pkb ( pkb );
+	free_iob ( iobuf );
 	return -1;
 }
 
diff --git a/src/net/ndp.c b/src/net/ndp.c
index 11085a43..7c684e7c 100644
--- a/src/net/ndp.c
+++ b/src/net/ndp.c
@@ -3,7 +3,7 @@
 #include <byteswap.h>
 #include <errno.h>
 #include <gpxe/if_ether.h>
-#include <gpxe/pkbuff.h>
+#include <gpxe/iobuf.h>
 #include <gpxe/ndp.h>
 #include <gpxe/icmp6.h>
 #include <gpxe/ip6.h>
@@ -143,18 +143,18 @@ int ndp_resolve ( struct net_device *netdev, struct in6_addr *dest,
 /**
  * Process neighbour advertisement
  *
- * @v pkb	Packet buffer
+ * @v iobuf	I/O buffer
  * @v st_src	Source address
  * @v st_dest	Destination address 
  */
-int ndp_process_advert ( struct pk_buff *pkb, struct sockaddr_tcpip *st_src __unused,
+int ndp_process_advert ( struct io_buffer *iobuf, struct sockaddr_tcpip *st_src __unused,
 			   struct sockaddr_tcpip *st_dest __unused ) {
-	struct neighbour_advert *nadvert = pkb->data;
+	struct neighbour_advert *nadvert = iobuf->data;
 	struct ndp_entry *ndp;
 
 	/* Sanity check */
-	if ( pkb_len ( pkb ) < sizeof ( *nadvert ) ) {
-		DBG ( "Packet too short (%d bytes)\n", pkb_len ( pkb ) );
+	if ( iob_len ( iobuf ) < sizeof ( *nadvert ) ) {
+		DBG ( "Packet too short (%d bytes)\n", iob_len ( iobuf ) );
 		return -EINVAL;
 	}
 
diff --git a/src/net/netdevice.c b/src/net/netdevice.c
index d498d9f1..c1ad5f68 100644
--- a/src/net/netdevice.c
+++ b/src/net/netdevice.c
@@ -23,7 +23,7 @@
 #include <string.h>
 #include <errno.h>
 #include <gpxe/if_ether.h>
-#include <gpxe/pkbuff.h>
+#include <gpxe/iobuf.h>
 #include <gpxe/tables.h>
 #include <gpxe/process.h>
 #include <gpxe/init.h>
@@ -49,34 +49,34 @@ struct list_head net_devices = LIST_HEAD_INIT ( net_devices );
  * Transmit raw packet via network device
  *
  * @v netdev		Network device
- * @v pkb		Packet buffer
+ * @v iobuf		I/O buffer
  * @ret rc		Return status code
  *
  * Transmits the packet via the specified network device.  This
- * function takes ownership of the packet buffer.
+ * function takes ownership of the I/O buffer.
  */
-int netdev_tx ( struct net_device *netdev, struct pk_buff *pkb ) {
+int netdev_tx ( struct net_device *netdev, struct io_buffer *iobuf ) {
 	int rc;
 
 	DBGC ( netdev, "NETDEV %p transmitting %p (%p+%zx)\n",
-	       netdev, pkb, pkb->data, pkb_len ( pkb ) );
+	       netdev, iobuf, iobuf->data, iob_len ( iobuf ) );
 
-	list_add_tail ( &pkb->list, &netdev->tx_queue );
+	list_add_tail ( &iobuf->list, &netdev->tx_queue );
 
 	if ( ! ( netdev->state & NETDEV_OPEN ) ) {
 		rc = -ENETUNREACH;
 		goto err;
 	}
 		
-	if ( ( rc = netdev->transmit ( netdev, pkb ) ) != 0 )
+	if ( ( rc = netdev->transmit ( netdev, iobuf ) ) != 0 )
 		goto err;
 
 	return 0;
 
  err:
 	DBGC ( netdev, "NETDEV %p transmission %p failed: %s\n",
-	       netdev, pkb, strerror ( rc ) );
-	netdev_tx_complete ( netdev, pkb );
+	       netdev, iobuf, strerror ( rc ) );
+	netdev_tx_complete ( netdev, iobuf );
 	return rc;
 }
 
@@ -84,19 +84,19 @@ int netdev_tx ( struct net_device *netdev, struct pk_buff *pkb ) {
  * Complete network transmission
  *
  * @v netdev		Network device
- * @v pkb		Packet buffer
+ * @v iobuf		I/O buffer
  *
  * The packet must currently be in the network device's TX queue.
  */
-void netdev_tx_complete ( struct net_device *netdev, struct pk_buff *pkb ) {
-	DBGC ( netdev, "NETDEV %p transmission %p complete\n", netdev, pkb );
+void netdev_tx_complete ( struct net_device *netdev, struct io_buffer *iobuf ) {
+	DBGC ( netdev, "NETDEV %p transmission %p complete\n", netdev, iobuf );
 
 	/* Catch data corruption as early as possible */
-	assert ( pkb->list.next != NULL );
-	assert ( pkb->list.prev != NULL );
+	assert ( iobuf->list.next != NULL );
+	assert ( iobuf->list.prev != NULL );
 
-	list_del ( &pkb->list );
-	free_pkb ( pkb );
+	list_del ( &iobuf->list );
+	free_iob ( iobuf );
 }
 
 /**
@@ -107,10 +107,10 @@ void netdev_tx_complete ( struct net_device *netdev, struct pk_buff *pkb ) {
  * Completes the oldest outstanding packet in the TX queue.
  */
 void netdev_tx_complete_next ( struct net_device *netdev ) {
-	struct pk_buff *pkb;
+	struct io_buffer *iobuf;
 
-	list_for_each_entry ( pkb, &netdev->tx_queue, list ) {
-		netdev_tx_complete ( netdev, pkb );
+	list_for_each_entry ( iobuf, &netdev->tx_queue, list ) {
+		netdev_tx_complete ( netdev, iobuf );
 		return;
 	}
 }
@@ -119,15 +119,15 @@ void netdev_tx_complete_next ( struct net_device *netdev ) {
  * Add packet to receive queue
  *
  * @v netdev		Network device
- * @v pkb		Packet buffer
+ * @v iobuf		I/O buffer
  *
  * The packet is added to the network device's RX queue.  This
- * function takes ownership of the packet buffer.
+ * function takes ownership of the I/O buffer.
  */
-void netdev_rx ( struct net_device *netdev, struct pk_buff *pkb ) {
+void netdev_rx ( struct net_device *netdev, struct io_buffer *iobuf ) {
 	DBGC ( netdev, "NETDEV %p received %p (%p+%zx)\n",
-	       netdev, pkb, pkb->data, pkb_len ( pkb ) );
-	list_add_tail ( &pkb->list, &netdev->rx_queue );
+	       netdev, iobuf, iobuf->data, iob_len ( iobuf ) );
+	list_add_tail ( &iobuf->list, &netdev->rx_queue );
 }
 
 /**
@@ -153,17 +153,17 @@ int netdev_poll ( struct net_device *netdev, unsigned int rx_quota ) {
  * Remove packet from device's receive queue
  *
  * @v netdev		Network device
- * @ret pkb		Packet buffer, or NULL
+ * @ret iobuf		I/O buffer, or NULL
  *
  * Removes the first packet from the device's RX queue and returns it.
  * Ownership of the packet is transferred to the caller.
  */
-struct pk_buff * netdev_rx_dequeue ( struct net_device *netdev ) {
-	struct pk_buff *pkb;
+struct io_buffer * netdev_rx_dequeue ( struct net_device *netdev ) {
+	struct io_buffer *iobuf;
 
-	list_for_each_entry ( pkb, &netdev->rx_queue, list ) {
-		list_del ( &pkb->list );
-		return pkb;
+	list_for_each_entry ( iobuf, &netdev->rx_queue, list ) {
+		list_del ( &iobuf->list );
+		return iobuf;
 	}
 	return NULL;
 }
@@ -247,7 +247,7 @@ int netdev_open ( struct net_device *netdev ) {
  * @v netdev		Network device
  */
 void netdev_close ( struct net_device *netdev ) {
-	struct pk_buff *pkb;
+	struct io_buffer *iobuf;
 
 	/* Do nothing if device is already closed */
 	if ( ! ( netdev->state & NETDEV_OPEN ) )
@@ -264,10 +264,10 @@ void netdev_close ( struct net_device *netdev ) {
 	}
 
 	/* Discard any packets in the RX queue */
-	while ( ( pkb = netdev_rx_dequeue ( netdev ) ) ) {
+	while ( ( iobuf = netdev_rx_dequeue ( netdev ) ) ) {
 		DBGC ( netdev, "NETDEV %p discarding received %p\n",
-		       netdev, pkb );
-		free_pkb ( pkb );
+		       netdev, iobuf );
+		free_iob ( iobuf );
 	}
 
 	/* Mark as closed */
@@ -341,31 +341,31 @@ struct net_device * find_pci_netdev ( unsigned int busdevfn ) {
 /**
  * Transmit network-layer packet
  *
- * @v pkb		Packet buffer
+ * @v iobuf		I/O buffer
  * @v netdev		Network device
  * @v net_protocol	Network-layer protocol
  * @v ll_dest		Destination link-layer address
  * @ret rc		Return status code
  *
- * Prepends link-layer headers to the packet buffer and transmits the
+ * Prepends link-layer headers to the I/O buffer and transmits the
  * packet via the specified network device.  This function takes
- * ownership of the packet buffer.
+ * ownership of the I/O buffer.
  */
-int net_tx ( struct pk_buff *pkb, struct net_device *netdev,
+int net_tx ( struct io_buffer *iobuf, struct net_device *netdev,
 	     struct net_protocol *net_protocol, const void *ll_dest ) {
-	return netdev->ll_protocol->tx ( pkb, netdev, net_protocol, ll_dest );
+	return netdev->ll_protocol->tx ( iobuf, netdev, net_protocol, ll_dest );
 }
 
 /**
  * Process received network-layer packet
  *
- * @v pkb		Packet buffer
+ * @v iobuf		I/O buffer
  * @v netdev		Network device
  * @v net_proto		Network-layer protocol, in network-byte order
  * @v ll_source		Source link-layer address
  * @ret rc		Return status code
  */
-int net_rx ( struct pk_buff *pkb, struct net_device *netdev,
+int net_rx ( struct io_buffer *iobuf, struct net_device *netdev,
 	     uint16_t net_proto, const void *ll_source ) {
 	struct net_protocol *net_protocol;
 
@@ -373,10 +373,10 @@ int net_rx ( struct pk_buff *pkb, struct net_device *netdev,
 	for ( net_protocol = net_protocols ; net_protocol < net_protocols_end ;
 	      net_protocol++ ) {
 		if ( net_protocol->net_proto == net_proto ) {
-			return net_protocol->rx ( pkb, netdev, ll_source );
+			return net_protocol->rx ( iobuf, netdev, ll_source );
 		}
 	}
-	free_pkb ( pkb );
+	free_iob ( iobuf );
 	return 0;
 }
 
@@ -390,7 +390,7 @@ int net_rx ( struct pk_buff *pkb, struct net_device *netdev,
  */
 static void net_step ( struct process *process ) {
 	struct net_device *netdev;
-	struct pk_buff *pkb;
+	struct io_buffer *iobuf;
 
 	/* Poll and process each network device */
 	list_for_each_entry ( netdev, &net_devices, list ) {
@@ -404,10 +404,10 @@ static void net_step ( struct process *process ) {
 		 * that assumes that we can receive packets from the
 		 * NIC faster than they arrive.
 		 */
-		if ( ( pkb = netdev_rx_dequeue ( netdev ) ) ) {
+		if ( ( iobuf = netdev_rx_dequeue ( netdev ) ) ) {
 			DBGC ( netdev, "NETDEV %p processing %p\n",
-			       netdev, pkb );
-			netdev->ll_protocol->rx ( pkb, netdev );
+			       netdev, iobuf );
+			netdev->ll_protocol->rx ( iobuf, netdev );
 		}
 	}
 
diff --git a/src/net/pkbpad.c b/src/net/pkbpad.c
index e12e46b9..9961edca 100644
--- a/src/net/pkbpad.c
+++ b/src/net/pkbpad.c
@@ -19,48 +19,48 @@
 /**
  * @file
  *
- * Packet buffer padding
+ * I/O buffer padding
  *
  */
 
 #include <string.h>
-#include <gpxe/pkbuff.h>
+#include <gpxe/iobuf.h>
 
 /**
- * Pad packet buffer
+ * Pad I/O buffer
  *
- * @v pkb		Packet buffer
+ * @v iobuf		I/O buffer
  * @v min_len		Minimum length
  *
- * This function pads and aligns packet buffers, for devices that
+ * This function pads and aligns I/O buffers, for devices that
  * aren't capable of padding in hardware, or that require specific
  * alignment in TX buffers.  The packet data will end up aligned to a
- * multiple of @c PKB_ALIGN.
+ * multiple of @c IOB_ALIGN.
  *
- * @c min_len must not exceed @v PKB_ZLEN.
+ * @c min_len must not exceed @v IOB_ZLEN.
  */
-void pkb_pad ( struct pk_buff *pkb, size_t min_len ) {
+void iob_pad ( struct io_buffer *iobuf, size_t min_len ) {
 	void *data;
 	size_t len;
 	size_t headroom;
 	signed int pad_len;
 
-	assert ( min_len <= PKB_ZLEN );
+	assert ( min_len <= IOB_ZLEN );
 
-	/* Move packet data to start of packet buffer.  This will both
-	 * align the data (since packet buffers are aligned to
-	 * PKB_ALIGN) and give us sufficient space for the
+	/* Move packet data to start of I/O buffer.  This will both
+	 * align the data (since I/O buffers are aligned to
+	 * IOB_ALIGN) and give us sufficient space for the
 	 * zero-padding
 	 */
-	data = pkb->data;
-	len = pkb_len ( pkb );
-	headroom = pkb_headroom ( pkb );
-	pkb_push ( pkb, headroom );
-	memmove ( pkb->data, data, len );
-	pkb_unput ( pkb, headroom );
+	data = iobuf->data;
+	len = iob_len ( iobuf );
+	headroom = iob_headroom ( iobuf );
+	iob_push ( iobuf, headroom );
+	memmove ( iobuf->data, data, len );
+	iob_unput ( iobuf, headroom );
 
 	/* Pad to minimum packet length */
-	pad_len = ( min_len - pkb_len ( pkb ) );
+	pad_len = ( min_len - iob_len ( iobuf ) );
 	if ( pad_len > 0 )
-		memset ( pkb_put ( pkb, pad_len ), 0, pad_len );
+		memset ( iob_put ( iobuf, pad_len ), 0, pad_len );
 }
diff --git a/src/net/pkbuff.c b/src/net/pkbuff.c
deleted file mode 100644
index 63bc95f0..00000000
--- a/src/net/pkbuff.c
+++ /dev/null
@@ -1,73 +0,0 @@
-/*
- * Copyright (C) 2006 Michael Brown <mbrown@fensystems.co.uk>.
- *
- * This program is free software; you can redistribute it and/or
- * modify it under the terms of the GNU General Public License as
- * published by the Free Software Foundation; either version 2 of the
- * License, or any later version.
- *
- * This program is distributed in the hope that it will be useful, but
- * WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
- * General Public License for more details.
- *
- * You should have received a copy of the GNU General Public License
- * along with this program; if not, write to the Free Software
- * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
- */
-
-#include <stdint.h>
-#include <gpxe/malloc.h>
-#include <gpxe/pkbuff.h>
-
-/** @file
- *
- * Packet buffers
- *
- */
-
-/**
- * Allocate packet buffer
- *
- * @v len	Required length of buffer
- * @ret pkb	Packet buffer, or NULL if none available
- *
- * The packet buffer will be physically aligned to a multiple of
- * @c PKBUFF_SIZE.
- */
-struct pk_buff * alloc_pkb ( size_t len ) {
-	struct pk_buff *pkb = NULL;
-	void *data;
-
-	/* Pad to minimum length */
-	if ( len < PKB_ZLEN )
-		len = PKB_ZLEN;
-
-	/* Align buffer length */
-	len = ( len + __alignof__( *pkb ) - 1 ) & ~( __alignof__( *pkb ) - 1 );
-	
-	/* Allocate memory for buffer plus descriptor */
-	data = malloc_dma ( len + sizeof ( *pkb ), PKBUFF_ALIGN );
-	if ( ! data )
-		return NULL;
-
-	pkb = ( struct pk_buff * ) ( data + len );
-	pkb->head = pkb->data = pkb->tail = data;
-	pkb->end = pkb;
-	return pkb;
-}
-
-/**
- * Free packet buffer
- *
- * @v pkb	Packet buffer
- */
-void free_pkb ( struct pk_buff *pkb ) {
-	if ( pkb ) {
-		assert ( pkb->head <= pkb->data );
-		assert ( pkb->data <= pkb->tail );
-		assert ( pkb->tail <= pkb->end );
-		free_dma ( pkb->head,
-			   ( pkb->end - pkb->head ) + sizeof ( *pkb ) );
-	}
-}
diff --git a/src/net/tcp.c b/src/net/tcp.c
index 96cac772..909f58f4 100644
--- a/src/net/tcp.c
+++ b/src/net/tcp.c
@@ -5,7 +5,7 @@
 #include <errno.h>
 #include <byteswap.h>
 #include <timer.h>
-#include <gpxe/pkbuff.h>
+#include <gpxe/iobuf.h>
 #include <gpxe/malloc.h>
 #include <gpxe/retry.h>
 #include <gpxe/stream.h>
@@ -68,12 +68,12 @@ struct tcp_connection {
 	 */
 	uint32_t rcv_ack;
 
-	/** Transmit packet buffer
+	/** Transmit I/O buffer
 	 *
 	 * This buffer is allocated prior to calling the application's
 	 * senddata() method, to provide temporary storage space.
 	 */
-	struct pk_buff *tx_pkb;
+	struct io_buffer *tx_iob;
 	/** Retransmission timer */
 	struct retry_timer timer;
 };
@@ -222,7 +222,7 @@ static void tcp_abort ( struct tcp_connection *tcp, int send_rst, int rc ) {
  * eventually attempt to retransmit the failed packet.
  */
 static int tcp_senddata_conn ( struct tcp_connection *tcp, int force_send ) {
-	struct pk_buff *pkb;
+	struct io_buffer *iobuf;
 	struct tcp_header *tcphdr;
 	struct tcp_mss_option *mssopt;
 	void *payload;
@@ -233,12 +233,12 @@ static int tcp_senddata_conn ( struct tcp_connection *tcp, int force_send ) {
 	int rc;
 
 	/* Allocate space to the TX buffer */
-	pkb = alloc_pkb ( MAX_PKB_LEN );
-	if ( ! pkb ) {
+	iobuf = alloc_iob ( MAX_IOB_LEN );
+	if ( ! iobuf ) {
 		DBGC ( tcp, "TCP %p could not allocate data buffer\n", tcp );
 		/* Start the retry timer so that we attempt to
 		 * retransmit this packet later.  (Start it
-		 * unconditionally, since without a packet buffer we
+		 * unconditionally, since without a I/O buffer we
 		 * can't call the senddata() callback, and so may not
 		 * be able to tell whether or not we have something
 		 * that actually needs to be retransmitted).
@@ -246,20 +246,20 @@ static int tcp_senddata_conn ( struct tcp_connection *tcp, int force_send ) {
 		start_timer ( &tcp->timer );
 		return -ENOMEM;
 	}
-	pkb_reserve ( pkb, MAX_HDR_LEN );
+	iob_reserve ( iobuf, MAX_HDR_LEN );
 
 	/* If we are connected, call the senddata() method, which may
 	 * call tcp_send() to queue up a data payload.
 	 */
 	if ( TCP_CAN_SEND_DATA ( tcp->tcp_state ) ) {
-		tcp->tx_pkb = pkb;
-		stream_senddata ( &tcp->stream, pkb->data,
-				  pkb_tailroom ( pkb ) );
-		tcp->tx_pkb = NULL;
+		tcp->tx_iob = iobuf;
+		stream_senddata ( &tcp->stream, iobuf->data,
+				  iob_tailroom ( iobuf ) );
+		tcp->tx_iob = NULL;
 	}
 
 	/* Truncate payload length to fit transmit window */
-	len = pkb_len ( pkb );
+	len = iob_len ( iobuf );
 	if ( len > tcp->snd_win )
 		len = tcp->snd_win;
 
@@ -276,7 +276,7 @@ static int tcp_senddata_conn ( struct tcp_connection *tcp, int force_send ) {
 
 	/* If we have nothing to transmit, drop the packet */
 	if ( ( seq_len == 0 ) && ! force_send ) {
-		free_pkb ( pkb );
+		free_iob ( iobuf );
 		return 0;
 	}
 
@@ -294,23 +294,23 @@ static int tcp_senddata_conn ( struct tcp_connection *tcp, int force_send ) {
 	window &= ~0x03; /* Keep everything dword-aligned */
 
 	/* Fill up the TCP header */
-	payload = pkb->data;
+	payload = iobuf->data;
 	if ( flags & TCP_SYN ) {
-		mssopt = pkb_push ( pkb, sizeof ( *mssopt ) );
+		mssopt = iob_push ( iobuf, sizeof ( *mssopt ) );
 		mssopt->kind = TCP_OPTION_MSS;
 		mssopt->length = sizeof ( *mssopt );
 		mssopt->mss = htons ( TCP_MSS );
 	}
-	tcphdr = pkb_push ( pkb, sizeof ( *tcphdr ) );
+	tcphdr = iob_push ( iobuf, sizeof ( *tcphdr ) );
 	memset ( tcphdr, 0, sizeof ( *tcphdr ) );
 	tcphdr->src = tcp->local_port;
 	tcphdr->dest = tcp->peer.st_port;
 	tcphdr->seq = htonl ( tcp->snd_seq );
 	tcphdr->ack = htonl ( tcp->rcv_ack );
-	tcphdr->hlen = ( ( payload - pkb->data ) << 2 );
+	tcphdr->hlen = ( ( payload - iobuf->data ) << 2 );
 	tcphdr->flags = flags;
 	tcphdr->win = htons ( window );
-	tcphdr->csum = tcpip_chksum ( pkb->data, pkb_len ( pkb ) );
+	tcphdr->csum = tcpip_chksum ( iobuf->data, iob_len ( iobuf ) );
 
 	/* Dump header */
 	DBGC ( tcp, "TCP %p TX %d->%d %08lx..%08lx           %08lx %4zd",
@@ -321,7 +321,7 @@ static int tcp_senddata_conn ( struct tcp_connection *tcp, int force_send ) {
 	DBGC ( tcp, "\n" );
 
 	/* Transmit packet */
-	rc = tcpip_tx ( pkb, &tcp_protocol, &tcp->peer, NULL, &tcphdr->csum );
+	rc = tcpip_tx ( iobuf, &tcp_protocol, &tcp->peer, NULL, &tcphdr->csum );
 
 	/* If we got -ENETUNREACH, kill the connection immediately
 	 * because there is no point retrying.  This isn't strictly
@@ -372,22 +372,22 @@ static int tcp_send ( struct stream_connection *stream,
 		      const void *data, size_t len ) {
 	struct tcp_connection *tcp =
 		container_of ( stream, struct tcp_connection, stream );
-	struct pk_buff *pkb;
+	struct io_buffer *iobuf;
 
-	/* Check that we have a packet buffer to fill */
-	pkb = tcp->tx_pkb;
-	if ( ! pkb ) {
+	/* Check that we have a I/O buffer to fill */
+	iobuf = tcp->tx_iob;
+	if ( ! iobuf ) {
 		DBGC ( tcp, "TCP %p tried to send data outside of the "
 		       "senddata() method\n", tcp );
 		return -EINVAL;
 	}
 
-	/* Truncate length to fit packet buffer */
-	if ( len > pkb_tailroom ( pkb ) )
-		len = pkb_tailroom ( pkb );
+	/* Truncate length to fit I/O buffer */
+	if ( len > iob_tailroom ( iobuf ) )
+		len = iob_tailroom ( iobuf );
 
 	/* Copy payload */
-	memmove ( pkb_put ( pkb, len ), data, len );
+	memmove ( iob_put ( iobuf, len ), data, len );
 
 	return 0;
 }
@@ -434,19 +434,19 @@ static void tcp_expired ( struct retry_timer *timer, int over ) {
  */
 static int tcp_send_reset ( struct tcp_connection *tcp,
 			    struct tcp_header *in_tcphdr ) {
-	struct pk_buff *pkb;
+	struct io_buffer *iobuf;
 	struct tcp_header *tcphdr;
 
 	/* Allocate space for dataless TX buffer */
-	pkb = alloc_pkb ( MAX_HDR_LEN );
-	if ( ! pkb ) {
+	iobuf = alloc_iob ( MAX_HDR_LEN );
+	if ( ! iobuf ) {
 		DBGC ( tcp, "TCP %p could not allocate data buffer\n", tcp );
 		return -ENOMEM;
 	}
-	pkb_reserve ( pkb, MAX_HDR_LEN );
+	iob_reserve ( iobuf, MAX_HDR_LEN );
 
 	/* Construct RST response */
-	tcphdr = pkb_push ( pkb, sizeof ( *tcphdr ) );
+	tcphdr = iob_push ( iobuf, sizeof ( *tcphdr ) );
 	memset ( tcphdr, 0, sizeof ( *tcphdr ) );
 	tcphdr->src = in_tcphdr->dest;
 	tcphdr->dest = in_tcphdr->src;
@@ -455,7 +455,7 @@ static int tcp_send_reset ( struct tcp_connection *tcp,
 	tcphdr->hlen = ( ( sizeof ( *tcphdr ) / 4 ) << 4 );
 	tcphdr->flags = ( TCP_RST | TCP_ACK );
 	tcphdr->win = htons ( TCP_MAX_WINDOW_SIZE );
-	tcphdr->csum = tcpip_chksum ( pkb->data, pkb_len ( pkb ) );
+	tcphdr->csum = tcpip_chksum ( iobuf->data, iob_len ( iobuf ) );
 
 	/* Dump header */
 	DBGC ( tcp, "TCP %p TX %d->%d %08lx..%08lx           %08lx %4zd",
@@ -466,7 +466,7 @@ static int tcp_send_reset ( struct tcp_connection *tcp,
 	DBGC ( tcp, "\n" );
 
 	/* Transmit packet */
-	return tcpip_tx ( pkb, &tcp_protocol, &tcp->peer,
+	return tcpip_tx ( iobuf, &tcp_protocol, &tcp->peer,
 			  NULL, &tcphdr->csum );
 }
 
@@ -662,17 +662,17 @@ static int tcp_rx_rst ( struct tcp_connection *tcp, uint32_t seq ) {
 /**
  * Process received packet
  *
- * @v pkb		Packet buffer
+ * @v iobuf		I/O buffer
  * @v st_src		Partially-filled source address
  * @v st_dest		Partially-filled destination address
  * @v pshdr_csum	Pseudo-header checksum
  * @ret rc		Return status code
   */
-static int tcp_rx ( struct pk_buff *pkb,
+static int tcp_rx ( struct io_buffer *iobuf,
 		    struct sockaddr_tcpip *st_src __unused,
 		    struct sockaddr_tcpip *st_dest __unused,
 		    uint16_t pshdr_csum ) {
-	struct tcp_header *tcphdr = pkb->data;
+	struct tcp_header *tcphdr = iobuf->data;
 	struct tcp_connection *tcp;
 	unsigned int hlen;
 	uint16_t csum;
@@ -686,9 +686,9 @@ static int tcp_rx ( struct pk_buff *pkb,
 	int rc;
 
 	/* Sanity check packet */
-	if ( pkb_len ( pkb ) < sizeof ( *tcphdr ) ) {
+	if ( iob_len ( iobuf ) < sizeof ( *tcphdr ) ) {
 		DBG ( "TCP packet too short at %d bytes (min %d bytes)\n",
-		      pkb_len ( pkb ), sizeof ( *tcphdr ) );
+		      iob_len ( iobuf ), sizeof ( *tcphdr ) );
 		rc = -EINVAL;
 		goto done;
 	}
@@ -699,13 +699,13 @@ static int tcp_rx ( struct pk_buff *pkb,
 		rc = -EINVAL;
 		goto done;
 	}
-	if ( hlen > pkb_len ( pkb ) ) {
+	if ( hlen > iob_len ( iobuf ) ) {
 		DBG ( "TCP header too long at %d bytes (max %d bytes)\n",
-		      hlen, pkb_len ( pkb ) );
+		      hlen, iob_len ( iobuf ) );
 		rc = -EINVAL;
 		goto done;
 	}
-	csum = tcpip_continue_chksum ( pshdr_csum, pkb->data, pkb_len ( pkb ));
+	csum = tcpip_continue_chksum ( pshdr_csum, iobuf->data, iob_len ( iobuf ));
 	if ( csum != 0 ) {
 		DBG ( "TCP checksum incorrect (is %04x including checksum "
 		      "field, should be 0000)\n", csum );
@@ -719,8 +719,8 @@ static int tcp_rx ( struct pk_buff *pkb,
 	ack = ntohl ( tcphdr->ack );
 	win = ntohs ( tcphdr->win );
 	flags = tcphdr->flags;
-	data = pkb_pull ( pkb, hlen );
-	len = pkb_len ( pkb );
+	data = iob_pull ( iobuf, hlen );
+	len = iob_len ( iobuf );
 
 	/* Dump header */
 	DBGC ( tcp, "TCP %p RX %d<-%d           %08lx %08lx..%08lx %4zd",
@@ -787,7 +787,7 @@ static int tcp_rx ( struct pk_buff *pkb,
 	rc = 0;
  done:
 	/* Free received packet */
-	free_pkb ( pkb );
+	free_iob ( iobuf );
 	return rc;
 }
 
diff --git a/src/net/tcpip.c b/src/net/tcpip.c
index 26565a5b..1bc8d1a3 100644
--- a/src/net/tcpip.c
+++ b/src/net/tcpip.c
@@ -2,7 +2,7 @@
 #include <string.h>
 #include <errno.h>
 #include <byteswap.h>
-#include <gpxe/pkbuff.h>
+#include <gpxe/iobuf.h>
 #include <gpxe/tables.h>
 #include <gpxe/tcpip.h>
 
@@ -28,7 +28,7 @@ static struct tcpip_protocol tcpip_protocols_end[0]
 
 /** Process a received TCP/IP packet
  *
- * @v pkb		Packet buffer
+ * @v iobuf		I/O buffer
  * @v tcpip_proto	Transport-layer protocol number
  * @v st_src		Partially-filled source address
  * @v st_dest		Partially-filled destination address
@@ -41,7 +41,7 @@ static struct tcpip_protocol tcpip_protocols_end[0]
  * address family and the network-layer addresses, but leave the ports
  * and the rest of the structures as zero).
  */
-int tcpip_rx ( struct pk_buff *pkb, uint8_t tcpip_proto, 
+int tcpip_rx ( struct io_buffer *iobuf, uint8_t tcpip_proto, 
 	       struct sockaddr_tcpip *st_src,
 	       struct sockaddr_tcpip *st_dest,
 	       uint16_t pshdr_csum ) {
@@ -51,25 +51,25 @@ int tcpip_rx ( struct pk_buff *pkb, uint8_t tcpip_proto,
 	for ( tcpip = tcpip_protocols; tcpip < tcpip_protocols_end; tcpip++ ) {
 		if ( tcpip->tcpip_proto == tcpip_proto ) {
 			DBG ( "TCP/IP received %s packet\n", tcpip->name );
-			return tcpip->rx ( pkb, st_src, st_dest, pshdr_csum );
+			return tcpip->rx ( iobuf, st_src, st_dest, pshdr_csum );
 		}
 	}
 
 	DBG ( "Unrecognised TCP/IP protocol %d\n", tcpip_proto );
-	free_pkb ( pkb );
+	free_iob ( iobuf );
 	return -EPROTONOSUPPORT;
 }
 
 /** Transmit a TCP/IP packet
  *
- * @v pkb		Packet buffer
+ * @v iobuf		I/O buffer
  * @v tcpip_protocol	Transport-layer protocol
  * @v st_dest		Destination address
  * @v netdev		Network device to use if no route found, or NULL
  * @v trans_csum	Transport-layer checksum to complete, or NULL
  * @ret rc		Return status code
  */
-int tcpip_tx ( struct pk_buff *pkb, struct tcpip_protocol *tcpip_protocol,
+int tcpip_tx ( struct io_buffer *iobuf, struct tcpip_protocol *tcpip_protocol,
 	       struct sockaddr_tcpip *st_dest, struct net_device *netdev,
 	       uint16_t *trans_csum ) {
 	struct tcpip_net_protocol *tcpip_net;
@@ -79,13 +79,13 @@ int tcpip_tx ( struct pk_buff *pkb, struct tcpip_protocol *tcpip_protocol,
 	      tcpip_net < tcpip_net_protocols_end ; tcpip_net++ ) {
 		if ( tcpip_net->sa_family == st_dest->st_family ) {
 			DBG ( "TCP/IP sending %s packet\n", tcpip_net->name );
-			return tcpip_net->tx ( pkb, tcpip_protocol, st_dest,
+			return tcpip_net->tx ( iobuf, tcpip_protocol, st_dest,
 					       netdev, trans_csum );
 		}
 	}
 	
 	DBG ( "Unrecognised TCP/IP address family %d\n", st_dest->st_family );
-	free_pkb ( pkb );
+	free_iob ( iobuf );
 	return -EAFNOSUPPORT;
 }
 
diff --git a/src/net/udp.c b/src/net/udp.c
index 1f74d65b..3c30284b 100644
--- a/src/net/udp.c
+++ b/src/net/udp.c
@@ -4,7 +4,7 @@
 #include <byteswap.h>
 #include <errno.h>
 #include <gpxe/tcpip.h>
-#include <gpxe/pkbuff.h>
+#include <gpxe/iobuf.h>
 #include <gpxe/netdevice.h>
 #include <gpxe/udp.h>
 
@@ -89,22 +89,22 @@ void udp_close ( struct udp_connection *conn ) {
 }
 
 /**
- * Allocate packet buffer for UDP
+ * Allocate I/O buffer for UDP
  *
  * @v conn		UDP connection
- * @ret pkb		Packet buffer, or NULL
+ * @ret iobuf		I/O buffer, or NULL
  */
-static struct pk_buff * udp_alloc_pkb ( struct udp_connection *conn ) {
-	struct pk_buff *pkb;
+static struct io_buffer * udp_alloc_iob ( struct udp_connection *conn ) {
+	struct io_buffer *iobuf;
 
-	pkb = alloc_pkb ( UDP_MAX_TXPKB );
-	if ( ! pkb ) {
+	iobuf = alloc_iob ( UDP_MAX_TXIOB );
+	if ( ! iobuf ) {
 		DBGC ( conn, "UDP %p cannot allocate buffer of length %d\n",
-		       conn, UDP_MAX_TXPKB );
+		       conn, UDP_MAX_TXIOB );
 		return NULL;
 	}
-	pkb_reserve ( pkb, UDP_MAX_HLEN );
-	return pkb;
+	iob_reserve ( iobuf, UDP_MAX_HLEN );
+	return iobuf;
 }
 
 /**
@@ -119,20 +119,20 @@ static struct pk_buff * udp_alloc_pkb ( struct udp_connection *conn ) {
 int udp_senddata ( struct udp_connection *conn ) {
 	int rc;
 
-	conn->tx_pkb = udp_alloc_pkb ( conn );
-	if ( ! conn->tx_pkb )
+	conn->tx_iob = udp_alloc_iob ( conn );
+	if ( ! conn->tx_iob )
 		return -ENOMEM;
 
-	rc = conn->udp_op->senddata ( conn, conn->tx_pkb->data, 
-				      pkb_tailroom ( conn->tx_pkb ) );
+	rc = conn->udp_op->senddata ( conn, conn->tx_iob->data, 
+				      iob_tailroom ( conn->tx_iob ) );
 	if ( rc != 0 ) {
 		DBGC ( conn, "UDP %p application could not send packet: %s\n",
 		       conn, strerror ( rc ) );
 	}
 
-	if ( conn->tx_pkb ) {
-		free_pkb ( conn->tx_pkb );
-		conn->tx_pkb = NULL;
+	if ( conn->tx_iob ) {
+		free_iob ( conn->tx_iob );
+		conn->tx_iob = NULL;
 	}
 
 	return rc;
@@ -152,25 +152,25 @@ int udp_sendto_via ( struct udp_connection *conn, struct sockaddr_tcpip *peer,
 		     struct net_device *netdev, const void *data,
 		     size_t len ) {
        	struct udp_header *udphdr;
-	struct pk_buff *pkb;
+	struct io_buffer *iobuf;
 	int rc;
 
-	/* Use precreated packet buffer if one is available */
-	if ( conn->tx_pkb ) {
-		pkb = conn->tx_pkb;
-		conn->tx_pkb = NULL;
+	/* Use precreated I/O buffer if one is available */
+	if ( conn->tx_iob ) {
+		iobuf = conn->tx_iob;
+		conn->tx_iob = NULL;
 	} else {
-		pkb = udp_alloc_pkb ( conn );
-		if ( ! pkb )
+		iobuf = udp_alloc_iob ( conn );
+		if ( ! iobuf )
 			return -ENOMEM;
 	}
 
 	/* Avoid overflowing TX buffer */
-	if ( len > pkb_tailroom ( pkb ) )
-		len = pkb_tailroom ( pkb );
+	if ( len > iob_tailroom ( iobuf ) )
+		len = iob_tailroom ( iobuf );
 
 	/* Copy payload */
-	memmove ( pkb_put ( pkb, len ), data, len );
+	memmove ( iob_put ( iobuf, len ), data, len );
 
 	/*
 	 * Add the UDP header
@@ -178,10 +178,10 @@ int udp_sendto_via ( struct udp_connection *conn, struct sockaddr_tcpip *peer,
 	 * Covert all 16- and 32- bit integers into network btye order before
 	 * sending it over the network
 	 */
-	udphdr = pkb_push ( pkb, sizeof ( *udphdr ) );
+	udphdr = iob_push ( iobuf, sizeof ( *udphdr ) );
 	udphdr->dest_port = peer->st_port;
 	udphdr->source_port = conn->local_port;
-	udphdr->len = htons ( pkb_len ( pkb ) );
+	udphdr->len = htons ( iob_len ( iobuf ) );
 	udphdr->chksum = 0;
 	udphdr->chksum = tcpip_chksum ( udphdr, sizeof ( *udphdr ) + len );
 
@@ -191,7 +191,7 @@ int udp_sendto_via ( struct udp_connection *conn, struct sockaddr_tcpip *peer,
 	       ntohs ( udphdr->len ) );
 
 	/* Send it to the next layer for processing */
-	if ( ( rc = tcpip_tx ( pkb, &udp_protocol, peer, netdev,
+	if ( ( rc = tcpip_tx ( iobuf, &udp_protocol, peer, netdev,
 			       &udphdr->chksum ) ) != 0 ) {
 		DBGC ( conn, "UDP %p could not transmit packet: %s\n",
 		       conn, strerror ( rc ) );
@@ -248,24 +248,24 @@ static struct udp_connection * udp_demux ( uint16_t local_port ) {
 /**
  * Process a received packet
  *
- * @v pkb		Packet buffer
+ * @v iobuf		I/O buffer
  * @v st_src		Partially-filled source address
  * @v st_dest		Partially-filled destination address
  * @v pshdr_csum	Pseudo-header checksum
  * @ret rc		Return status code
  */
-static int udp_rx ( struct pk_buff *pkb, struct sockaddr_tcpip *st_src,
+static int udp_rx ( struct io_buffer *iobuf, struct sockaddr_tcpip *st_src,
 		    struct sockaddr_tcpip *st_dest, uint16_t pshdr_csum ) {
-	struct udp_header *udphdr = pkb->data;
+	struct udp_header *udphdr = iobuf->data;
 	struct udp_connection *conn;
 	size_t ulen;
 	uint16_t csum;
 	int rc = 0;
 
 	/* Sanity check packet */
-	if ( pkb_len ( pkb ) < sizeof ( *udphdr ) ) {
+	if ( iob_len ( iobuf ) < sizeof ( *udphdr ) ) {
 		DBG ( "UDP packet too short at %d bytes (min %d bytes)\n",
-		      pkb_len ( pkb ), sizeof ( *udphdr ) );
+		      iob_len ( iobuf ), sizeof ( *udphdr ) );
 		
 		rc = -EINVAL;
 		goto done;
@@ -277,14 +277,14 @@ static int udp_rx ( struct pk_buff *pkb, struct sockaddr_tcpip *st_src,
 		rc = -EINVAL;
 		goto done;
 	}
-	if ( ulen > pkb_len ( pkb ) ) {
+	if ( ulen > iob_len ( iobuf ) ) {
 		DBG ( "UDP length too long at %d bytes (packet is %d bytes)\n",
-		      ulen, pkb_len ( pkb ) );
+		      ulen, iob_len ( iobuf ) );
 		rc = -EINVAL;
 		goto done;
 	}
 	if ( udphdr->chksum ) {
-		csum = tcpip_continue_chksum ( pshdr_csum, pkb->data, ulen );
+		csum = tcpip_continue_chksum ( pshdr_csum, iobuf->data, ulen );
 		if ( csum != 0 ) {
 			DBG ( "UDP checksum incorrect (is %04x including "
 			      "checksum field, should be 0000)\n", csum );
@@ -297,8 +297,8 @@ static int udp_rx ( struct pk_buff *pkb, struct sockaddr_tcpip *st_src,
 	st_src->st_port = udphdr->source_port;
 	st_dest->st_port = udphdr->dest_port;
 	conn = udp_demux ( udphdr->dest_port );
-	pkb_unput ( pkb, ( pkb_len ( pkb ) - ulen ) );
-	pkb_pull ( pkb, sizeof ( *udphdr ) );
+	iob_unput ( iobuf, ( iob_len ( iobuf ) - ulen ) );
+	iob_pull ( iobuf, sizeof ( *udphdr ) );
 
 	/* Dump debugging information */
 	DBGC ( conn, "UDP %p RX %d<-%d len %zd\n", conn,
@@ -315,7 +315,7 @@ static int udp_rx ( struct pk_buff *pkb, struct sockaddr_tcpip *st_src,
 
 	/* Pass data to application */
 	if ( conn->udp_op->newdata ) {
-		rc = conn->udp_op->newdata ( conn, pkb->data, pkb_len ( pkb ),
+		rc = conn->udp_op->newdata ( conn, iobuf->data, iob_len ( iobuf ),
 				     st_src, st_dest );
 		if ( rc != 0 ) {
 			DBGC ( conn, "UDP %p application rejected packet: %s\n",
@@ -327,7 +327,7 @@ static int udp_rx ( struct pk_buff *pkb, struct sockaddr_tcpip *st_src,
 	}
 
  done:
-	free_pkb ( pkb );
+	free_iob ( iobuf );
 	return rc;
 }