From 82fd76f2c2aa0d56ca401d529f703ffe4b6fd3a0 Mon Sep 17 00:00:00 2001 From: Shaun Ruffell Date: Wed, 28 Jul 2010 15:32:02 +0000 Subject: wctc4xxp: Do not ACK response packets without a corresponding request. Closes a small window of opportunity where system conditions prevent the driver from servicing it's receive ring within the timeout period of a request, and then in the middle of retrying the request (after the request was already removed from the "waiting_for_response" list) the driver process the response, it's possible for the driver to ACK the response without ever pairing it up with the original request. The result being that the DTE will then ignore our attempts to retry the original request. DAHDI-430. git-svn-id: http://svn.asterisk.org/svn/dahdi/linux/trunk@9035 a0bf4364-ded3-4de4-8d8a-66a801d63aff --- drivers/dahdi/wctc4xxp/base.c | 47 ++++++++++++++++++++++++++++++++----------- 1 file changed, 35 insertions(+), 12 deletions(-) (limited to 'drivers/dahdi') diff --git a/drivers/dahdi/wctc4xxp/base.c b/drivers/dahdi/wctc4xxp/base.c index 03eda38..0bd19c7 100644 --- a/drivers/dahdi/wctc4xxp/base.c +++ b/drivers/dahdi/wctc4xxp/base.c @@ -1,5 +1,4 @@ -/* - * Wildcard TC400B Driver +/* Wildcard TC400B Driver * * Copyright (C) 2006-2010, Digium, Inc. * @@ -39,6 +38,8 @@ #include #include +#include + #include "dahdi/kernel.h" #if LINUX_VERSION_CODE < KERNEL_VERSION(2, 6, 18) @@ -2217,19 +2218,18 @@ wctc4xxp_send_ack(struct wcdte *wc, u8 seqno, __be16 channel) wctc4xxp_transmit_cmd(wc, cmd); } -static void -do_rx_response_packet(struct wcdte *wc, struct tcb *cmd) +static bool do_rx_response_packet(struct wcdte *wc, struct tcb *cmd) { const struct csm_encaps_hdr *listhdr, *rxhdr; struct tcb *pos, *temp; unsigned long flags; - u32 handled = 0; + bool handled = false; rxhdr = cmd->data; - if (0xffff == rxhdr->channel) { + if (SUPERVISOR_CHANNEL == rxhdr->channel) { /* We received a duplicate response. */ if (rxhdr->seq_num == wc->last_rx_seq_num) { free_cmd(cmd); - return; + return false; } wc->last_rx_seq_num = rxhdr->seq_num; } @@ -2250,7 +2250,7 @@ do_rx_response_packet(struct wcdte *wc, struct tcb *cmd) if (pos->flags & TX_COMPLETE) complete(&pos->complete); spin_unlock(&pos->lock); - handled = 1; + handled = true; break; } @@ -2262,7 +2262,10 @@ do_rx_response_packet(struct wcdte *wc, struct tcb *cmd) "Freeing unhandled response ch:(%04x)\n", be16_to_cpu(rxhdr->channel)); free_cmd(cmd); + return false; } + + return true; } static void @@ -2356,12 +2359,20 @@ receive_csm_encaps_packet(struct wcdte *wc, struct tcb *cmd) const struct csm_encaps_hdr *hdr = cmd->data; if (!(hdr->control & MESSAGE_PACKET)) { - if (!(hdr->control & SUPPRESS_ACK)) - wctc4xxp_send_ack(wc, hdr->seq_num, hdr->channel); - + const bool suppress_ack = ((hdr->control & SUPPRESS_ACK) > 0); if (is_response(hdr)) { - do_rx_response_packet(wc, cmd); + u8 seq_num = hdr->seq_num; + __be16 channel = hdr->channel; + + if (do_rx_response_packet(wc, cmd) && !suppress_ack) + wctc4xxp_send_ack(wc, seq_num, channel); + } else if (0xc1 == hdr->type) { + if (!suppress_ack) { + wctc4xxp_send_ack(wc, hdr->seq_num, + hdr->channel); + } + if (0x75 == hdr->class) { DTE_PRINTK(WARNING, "Received alert (0x%04x) from dsp\n", @@ -2369,6 +2380,10 @@ receive_csm_encaps_packet(struct wcdte *wc, struct tcb *cmd) } free_cmd(cmd); } else if (0xd4 == hdr->type) { + if (!suppress_ack) { + wctc4xxp_send_ack(wc, hdr->seq_num, + hdr->channel); + } if (hdr->params[0] != le16_to_cpu(0xffff)) { DTE_PRINTK(WARNING, "DTE Failed self test (%04x).\n", @@ -2384,10 +2399,18 @@ receive_csm_encaps_packet(struct wcdte *wc, struct tcb *cmd) } free_cmd(cmd); } else if (MONITOR_LIVE_INDICATION_TYPE == hdr->type) { + if (!suppress_ack) { + wctc4xxp_send_ack(wc, hdr->seq_num, + hdr->channel); + } DTE_PRINTK(WARNING, "Received diagnostic message:\n"); print_command(wc, cmd); free_cmd(cmd); } else { + if (!suppress_ack) { + wctc4xxp_send_ack(wc, hdr->seq_num, + hdr->channel); + } DTE_PRINTK(WARNING, "Unknown command type received. %02x\n", hdr->type); free_cmd(cmd); -- cgit v1.2.3