diff options
Diffstat (limited to 'src/net/tcp.c')
| -rw-r--r-- | src/net/tcp.c | 38 |
1 files changed, 38 insertions, 0 deletions
diff --git a/src/net/tcp.c b/src/net/tcp.c index 68128e84a..37a202ef1 100644 --- a/src/net/tcp.c +++ b/src/net/tcp.c @@ -113,6 +113,8 @@ struct tcp_connection { struct process process; /** Retransmission timer */ struct retry_timer timer; + /** Keepalive timer */ + struct retry_timer keepalive; /** Shutdown (TIME_WAIT) timer */ struct retry_timer wait; @@ -177,6 +179,7 @@ static struct profiler tcp_xfer_profiler __profiler = { .name = "tcp.xfer" }; static struct process_descriptor tcp_process_desc; static struct interface_descriptor tcp_xfer_desc; static void tcp_expired ( struct retry_timer *timer, int over ); +static void tcp_keepalive_expired ( struct retry_timer *timer, int over ); static void tcp_wait_expired ( struct retry_timer *timer, int over ); static struct tcp_connection * tcp_demux ( unsigned int local_port ); static int tcp_rx_ack ( struct tcp_connection *tcp, uint32_t ack, @@ -284,6 +287,7 @@ static int tcp_open ( struct interface *xfer, struct sockaddr *peer, intf_init ( &tcp->xfer, &tcp_xfer_desc, &tcp->refcnt ); process_init_stopped ( &tcp->process, &tcp_process_desc, &tcp->refcnt ); timer_init ( &tcp->timer, tcp_expired, &tcp->refcnt ); + timer_init ( &tcp->keepalive, tcp_keepalive_expired, &tcp->refcnt ); timer_init ( &tcp->wait, tcp_wait_expired, &tcp->refcnt ); tcp->prev_tcp_state = TCP_CLOSED; tcp->tcp_state = TCP_STATE_SENT ( TCP_SYN ); @@ -380,6 +384,7 @@ static void tcp_close ( struct tcp_connection *tcp, int rc ) { /* Remove from list and drop reference */ process_del ( &tcp->process ); stop_timer ( &tcp->timer ); + stop_timer ( &tcp->keepalive ); stop_timer ( &tcp->wait ); list_del ( &tcp->list ); ref_put ( &tcp->refcnt ); @@ -394,6 +399,9 @@ static void tcp_close ( struct tcp_connection *tcp, int rc ) { if ( ! ( tcp->tcp_state & TCP_STATE_ACKED ( TCP_SYN ) ) ) tcp_rx_ack ( tcp, ( tcp->snd_seq + 1 ), 0 ); + /* Stop keepalive timer */ + stop_timer ( &tcp->keepalive ); + /* If we have no data remaining to send, start sending FIN */ if ( list_empty ( &tcp->tx_queue ) && ! ( tcp->tcp_state & TCP_STATE_SENT ( TCP_FIN ) ) ) { @@ -802,6 +810,32 @@ static void tcp_expired ( struct retry_timer *timer, int over ) { } /** + * Keepalive timer expired + * + * @v timer Keepalive timer + * @v over Failure indicator + */ +static void tcp_keepalive_expired ( struct retry_timer *timer, + int over __unused ) { + struct tcp_connection *tcp = + container_of ( timer, struct tcp_connection, keepalive ); + + DBGC ( tcp, "TCP %p sending keepalive\n", tcp ); + + /* Reset keepalive timer */ + start_timer_fixed ( &tcp->keepalive, TCP_KEEPALIVE_DELAY ); + + /* Send keepalive. We do this only to preserve or restore + * state in intermediate devices (e.g. firewall NAT tables); + * we don't actually care about eliciting a response to verify + * that the peer is still alive. We therefore send just a + * pure ACK, to keep our transmit path simple. + */ + tcp->flags |= TCP_ACK_PENDING; + tcp_xmit ( tcp ); +} + +/** * Shutdown timer expired * * @v timer Shutdown timer @@ -1105,6 +1139,10 @@ static int tcp_rx_ack ( struct tcp_connection *tcp, uint32_t ack, /* Update window size */ tcp->snd_win = win; + /* Hold off (or start) the keepalive timer, if applicable */ + if ( ! ( tcp->tcp_state & TCP_STATE_SENT ( TCP_FIN ) ) ) + start_timer_fixed ( &tcp->keepalive, TCP_KEEPALIVE_DELAY ); + /* Ignore ACKs that don't actually acknowledge any new data. * (In particular, do not stop the retransmission timer; this * avoids creating a sorceror's apprentice syndrome when a |