From b453872c35cfcbdbf5a794737817f7d4e7b1b579 Mon Sep 17 00:00:00 2001 From: Jeff Garzik Date: Thu, 12 May 2005 22:48:20 -0400 Subject: [NET] ieee80211 subsystem Contributors: Host AP contributors James Ketrenos Francois Romieu Adrian Bunk Matthew Galgoci --- net/ieee80211/ieee80211_tx.c | 448 +++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 448 insertions(+) create mode 100644 net/ieee80211/ieee80211_tx.c (limited to 'net/ieee80211/ieee80211_tx.c') diff --git a/net/ieee80211/ieee80211_tx.c b/net/ieee80211/ieee80211_tx.c new file mode 100644 index 000000000000..d70e6b82715e --- /dev/null +++ b/net/ieee80211/ieee80211_tx.c @@ -0,0 +1,448 @@ +/****************************************************************************** + + Copyright(c) 2003 - 2004 Intel Corporation. All rights reserved. + + This program is free software; you can redistribute it and/or modify it + under the terms of version 2 of the GNU General Public License as + published by the Free Software Foundation. + + 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., 59 + Temple Place - Suite 330, Boston, MA 02111-1307, USA. + + The full GNU General Public License is included in this distribution in the + file called LICENSE. + + Contact Information: + James P. Ketrenos + Intel Corporation, 5200 N.E. Elam Young Parkway, Hillsboro, OR 97124-6497 + +******************************************************************************/ +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include + +#include + + +/* + + +802.11 Data Frame + + ,-------------------------------------------------------------------. +Bytes | 2 | 2 | 6 | 6 | 6 | 2 | 0..2312 | 4 | + |------|------|---------|---------|---------|------|---------|------| +Desc. | ctrl | dura | DA/RA | TA | SA | Sequ | Frame | fcs | + | | tion | (BSSID) | | | ence | data | | + `--------------------------------------------------| |------' +Total: 28 non-data bytes `----.----' + | + .- 'Frame data' expands to <---------------------------' + | + V + ,---------------------------------------------------. +Bytes | 1 | 1 | 1 | 3 | 2 | 0-2304 | + |------|------|---------|----------|------|---------| +Desc. | SNAP | SNAP | Control |Eth Tunnel| Type | IP | + | DSAP | SSAP | | | | Packet | + | 0xAA | 0xAA |0x03 (UI)|0x00-00-F8| | | + `-----------------------------------------| | +Total: 8 non-data bytes `----.----' + | + .- 'IP Packet' expands, if WEP enabled, to <--' + | + V + ,-----------------------. +Bytes | 4 | 0-2296 | 4 | + |-----|-----------|-----| +Desc. | IV | Encrypted | ICV | + | | IP Packet | | + `-----------------------' +Total: 8 non-data bytes + + +802.3 Ethernet Data Frame + + ,-----------------------------------------. +Bytes | 6 | 6 | 2 | Variable | 4 | + |-------|-------|------|-----------|------| +Desc. | Dest. | Source| Type | IP Packet | fcs | + | MAC | MAC | | | | + `-----------------------------------------' +Total: 18 non-data bytes + +In the event that fragmentation is required, the incoming payload is split into +N parts of size ieee->fts. The first fragment contains the SNAP header and the +remaining packets are just data. + +If encryption is enabled, each fragment payload size is reduced by enough space +to add the prefix and postfix (IV and ICV totalling 8 bytes in the case of WEP) +So if you have 1500 bytes of payload with ieee->fts set to 500 without +encryption it will take 3 frames. With WEP it will take 4 frames as the +payload of each frame is reduced to 492 bytes. + +* SKB visualization +* +* ,- skb->data +* | +* | ETHERNET HEADER ,-<-- PAYLOAD +* | | 14 bytes from skb->data +* | 2 bytes for Type --> ,T. | (sizeof ethhdr) +* | | | | +* |,-Dest.--. ,--Src.---. | | | +* | 6 bytes| | 6 bytes | | | | +* v | | | | | | +* 0 | v 1 | v | v 2 +* 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 +* ^ | ^ | ^ | +* | | | | | | +* | | | | `T' <---- 2 bytes for Type +* | | | | +* | | '---SNAP--' <-------- 6 bytes for SNAP +* | | +* `-IV--' <-------------------- 4 bytes for IV (WEP) +* +* SNAP HEADER +* +*/ + +static u8 P802_1H_OUI[P80211_OUI_LEN] = { 0x00, 0x00, 0xf8 }; +static u8 RFC1042_OUI[P80211_OUI_LEN] = { 0x00, 0x00, 0x00 }; + +static inline int ieee80211_put_snap(u8 *data, u16 h_proto) +{ + struct ieee80211_snap_hdr *snap; + u8 *oui; + + snap = (struct ieee80211_snap_hdr *)data; + snap->dsap = 0xaa; + snap->ssap = 0xaa; + snap->ctrl = 0x03; + + if (h_proto == 0x8137 || h_proto == 0x80f3) + oui = P802_1H_OUI; + else + oui = RFC1042_OUI; + snap->oui[0] = oui[0]; + snap->oui[1] = oui[1]; + snap->oui[2] = oui[2]; + + *(u16 *)(data + SNAP_SIZE) = htons(h_proto); + + return SNAP_SIZE + sizeof(u16); +} + +static inline int ieee80211_encrypt_fragment( + struct ieee80211_device *ieee, + struct sk_buff *frag, + int hdr_len) +{ + struct ieee80211_crypt_data* crypt = ieee->crypt[ieee->tx_keyidx]; + int res; + +#ifdef CONFIG_IEEE80211_CRYPT_TKIP + struct ieee80211_hdr *header; + + if (ieee->tkip_countermeasures && + crypt && crypt->ops && strcmp(crypt->ops->name, "TKIP") == 0) { + header = (struct ieee80211_hdr *) frag->data; + if (net_ratelimit()) { + printk(KERN_DEBUG "%s: TKIP countermeasures: dropped " + "TX packet to " MAC_FMT "\n", + ieee->dev->name, MAC_ARG(header->addr1)); + } + return -1; + } +#endif + /* To encrypt, frame format is: + * IV (4 bytes), clear payload (including SNAP), ICV (4 bytes) */ + + // PR: FIXME: Copied from hostap. Check fragmentation/MSDU/MPDU encryption. + /* Host-based IEEE 802.11 fragmentation for TX is not yet supported, so + * call both MSDU and MPDU encryption functions from here. */ + atomic_inc(&crypt->refcnt); + res = 0; + if (crypt->ops->encrypt_msdu) + res = crypt->ops->encrypt_msdu(frag, hdr_len, crypt->priv); + if (res == 0 && crypt->ops->encrypt_mpdu) + res = crypt->ops->encrypt_mpdu(frag, hdr_len, crypt->priv); + + atomic_dec(&crypt->refcnt); + if (res < 0) { + printk(KERN_INFO "%s: Encryption failed: len=%d.\n", + ieee->dev->name, frag->len); + ieee->ieee_stats.tx_discards++; + return -1; + } + + return 0; +} + + +void ieee80211_txb_free(struct ieee80211_txb *txb) { + int i; + if (unlikely(!txb)) + return; + for (i = 0; i < txb->nr_frags; i++) + if (txb->fragments[i]) + dev_kfree_skb_any(txb->fragments[i]); + kfree(txb); +} + +struct ieee80211_txb *ieee80211_alloc_txb(int nr_frags, int txb_size, + int gfp_mask) +{ + struct ieee80211_txb *txb; + int i; + txb = kmalloc( + sizeof(struct ieee80211_txb) + (sizeof(u8*) * nr_frags), + gfp_mask); + if (!txb) + return NULL; + + memset(txb, sizeof(struct ieee80211_txb), 0); + txb->nr_frags = nr_frags; + txb->frag_size = txb_size; + + for (i = 0; i < nr_frags; i++) { + txb->fragments[i] = dev_alloc_skb(txb_size); + if (unlikely(!txb->fragments[i])) { + i--; + break; + } + } + if (unlikely(i != nr_frags)) { + while (i >= 0) + dev_kfree_skb_any(txb->fragments[i--]); + kfree(txb); + return NULL; + } + return txb; +} + +/* SKBs are added to the ieee->tx_queue. */ +int ieee80211_xmit(struct sk_buff *skb, + struct net_device *dev) +{ + struct ieee80211_device *ieee = netdev_priv(dev); + struct ieee80211_txb *txb = NULL; + struct ieee80211_hdr *frag_hdr; + int i, bytes_per_frag, nr_frags, bytes_last_frag, frag_size; + unsigned long flags; + struct net_device_stats *stats = &ieee->stats; + int ether_type, encrypt; + int bytes, fc, hdr_len; + struct sk_buff *skb_frag; + struct ieee80211_hdr header = { /* Ensure zero initialized */ + .duration_id = 0, + .seq_ctl = 0 + }; + u8 dest[ETH_ALEN], src[ETH_ALEN]; + + struct ieee80211_crypt_data* crypt; + + spin_lock_irqsave(&ieee->lock, flags); + + /* If there is no driver handler to take the TXB, dont' bother + * creating it... */ + if (!ieee->hard_start_xmit) { + printk(KERN_WARNING "%s: No xmit handler.\n", + ieee->dev->name); + goto success; + } + + if (unlikely(skb->len < SNAP_SIZE + sizeof(u16))) { + printk(KERN_WARNING "%s: skb too small (%d).\n", + ieee->dev->name, skb->len); + goto success; + } + + ether_type = ntohs(((struct ethhdr *)skb->data)->h_proto); + + crypt = ieee->crypt[ieee->tx_keyidx]; + + encrypt = !(ether_type == ETH_P_PAE && ieee->ieee802_1x) && + ieee->host_encrypt && crypt && crypt->ops; + + if (!encrypt && ieee->ieee802_1x && + ieee->drop_unencrypted && ether_type != ETH_P_PAE) { + stats->tx_dropped++; + goto success; + } + +#ifdef CONFIG_IEEE80211_DEBUG + if (crypt && !encrypt && ether_type == ETH_P_PAE) { + struct eapol *eap = (struct eapol *)(skb->data + + sizeof(struct ethhdr) - SNAP_SIZE - sizeof(u16)); + IEEE80211_DEBUG_EAP("TX: IEEE 802.11 EAPOL frame: %s\n", + eap_get_type(eap->type)); + } +#endif + + /* Save source and destination addresses */ + memcpy(&dest, skb->data, ETH_ALEN); + memcpy(&src, skb->data+ETH_ALEN, ETH_ALEN); + + /* Advance the SKB to the start of the payload */ + skb_pull(skb, sizeof(struct ethhdr)); + + /* Determine total amount of storage required for TXB packets */ + bytes = skb->len + SNAP_SIZE + sizeof(u16); + + if (encrypt) + fc = IEEE80211_FTYPE_DATA | IEEE80211_STYPE_DATA | + IEEE80211_FCTL_WEP; + else + fc = IEEE80211_FTYPE_DATA | IEEE80211_STYPE_DATA; + + if (ieee->iw_mode == IW_MODE_INFRA) { + fc |= IEEE80211_FCTL_TODS; + /* To DS: Addr1 = BSSID, Addr2 = SA, + Addr3 = DA */ + memcpy(&header.addr1, ieee->bssid, ETH_ALEN); + memcpy(&header.addr2, &src, ETH_ALEN); + memcpy(&header.addr3, &dest, ETH_ALEN); + } else if (ieee->iw_mode == IW_MODE_ADHOC) { + /* not From/To DS: Addr1 = DA, Addr2 = SA, + Addr3 = BSSID */ + memcpy(&header.addr1, dest, ETH_ALEN); + memcpy(&header.addr2, src, ETH_ALEN); + memcpy(&header.addr3, ieee->bssid, ETH_ALEN); + } + header.frame_ctl = cpu_to_le16(fc); + hdr_len = IEEE80211_3ADDR_LEN; + + /* Determine fragmentation size based on destination (multicast + * and broadcast are not fragmented) */ + if (is_multicast_ether_addr(dest) || + is_broadcast_ether_addr(dest)) + frag_size = MAX_FRAG_THRESHOLD; + else + frag_size = ieee->fts; + + /* Determine amount of payload per fragment. Regardless of if + * this stack is providing the full 802.11 header, one will + * eventually be affixed to this fragment -- so we must account for + * it when determining the amount of payload space. */ + bytes_per_frag = frag_size - IEEE80211_3ADDR_LEN; + if (ieee->config & + (CFG_IEEE80211_COMPUTE_FCS | CFG_IEEE80211_RESERVE_FCS)) + bytes_per_frag -= IEEE80211_FCS_LEN; + + /* Each fragment may need to have room for encryptiong pre/postfix */ + if (encrypt) + bytes_per_frag -= crypt->ops->extra_prefix_len + + crypt->ops->extra_postfix_len; + + /* Number of fragments is the total bytes_per_frag / + * payload_per_fragment */ + nr_frags = bytes / bytes_per_frag; + bytes_last_frag = bytes % bytes_per_frag; + if (bytes_last_frag) + nr_frags++; + else + bytes_last_frag = bytes_per_frag; + + /* When we allocate the TXB we allocate enough space for the reserve + * and full fragment bytes (bytes_per_frag doesn't include prefix, + * postfix, header, FCS, etc.) */ + txb = ieee80211_alloc_txb(nr_frags, frag_size, GFP_ATOMIC); + if (unlikely(!txb)) { + printk(KERN_WARNING "%s: Could not allocate TXB\n", + ieee->dev->name); + goto failed; + } + txb->encrypted = encrypt; + txb->payload_size = bytes; + + for (i = 0; i < nr_frags; i++) { + skb_frag = txb->fragments[i]; + + if (encrypt) + skb_reserve(skb_frag, crypt->ops->extra_prefix_len); + + frag_hdr = (struct ieee80211_hdr *)skb_put(skb_frag, hdr_len); + memcpy(frag_hdr, &header, hdr_len); + + /* If this is not the last fragment, then add the MOREFRAGS + * bit to the frame control */ + if (i != nr_frags - 1) { + frag_hdr->frame_ctl = cpu_to_le16( + fc | IEEE80211_FCTL_MOREFRAGS); + bytes = bytes_per_frag; + } else { + /* The last fragment takes the remaining length */ + bytes = bytes_last_frag; + } + + /* Put a SNAP header on the first fragment */ + if (i == 0) { + ieee80211_put_snap( + skb_put(skb_frag, SNAP_SIZE + sizeof(u16)), + ether_type); + bytes -= SNAP_SIZE + sizeof(u16); + } + + memcpy(skb_put(skb_frag, bytes), skb->data, bytes); + + /* Advance the SKB... */ + skb_pull(skb, bytes); + + /* Encryption routine will move the header forward in order + * to insert the IV between the header and the payload */ + if (encrypt) + ieee80211_encrypt_fragment(ieee, skb_frag, hdr_len); + if (ieee->config & + (CFG_IEEE80211_COMPUTE_FCS | CFG_IEEE80211_RESERVE_FCS)) + skb_put(skb_frag, 4); + } + + + success: + spin_unlock_irqrestore(&ieee->lock, flags); + + dev_kfree_skb_any(skb); + + if (txb) { + if ((*ieee->hard_start_xmit)(txb, dev) == 0) { + stats->tx_packets++; + stats->tx_bytes += txb->payload_size; + return 0; + } + ieee80211_txb_free(txb); + } + + return 0; + + failed: + spin_unlock_irqrestore(&ieee->lock, flags); + netif_stop_queue(dev); + stats->tx_errors++; + return 1; + +} + +EXPORT_SYMBOL(ieee80211_txb_free); -- cgit v1.2.3-55-g7522