From a15a4c79ee752e48f928c2aa243c24a9cd8f263c Mon Sep 17 00:00:00 2001 From: Ben McKeegan Date: Fri, 24 Feb 2012 06:33:56 +0000 Subject: [PATCH] ppp: fix 'ppp_mp_reconstruct bad seq' errors [ Upstream commit 8a49ad6e89feb5015e77ce6efeb2678947117e20 ] This patch fixes a (mostly cosmetic) bug introduced by the patch 'ppp: Use SKB queue abstraction interfaces in fragment processing' found here: http://www.spinics.net/lists/netdev/msg153312.html The above patch rewrote and moved the code responsible for cleaning up discarded fragments but the new code does not catch every case where this is necessary. This results in some discarded fragments remaining in the queue, and triggering a 'bad seq' error on the subsequent call to ppp_mp_reconstruct. Fragments are discarded whenever other fragments of the same frame have been lost. This can generate a lot of unwanted and misleading log messages. This patch also adds additional detail to the debug logging to make it clearer which fragments were lost and which other fragments were discarded as a result of losses. (Run pppd with 'kdebug 1' option to enable debug logging.) Signed-off-by: Ben McKeegan Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman --- drivers/net/ppp/ppp_generic.c | 23 +++++++++++++++++++++++ 1 file changed, 23 insertions(+) diff --git a/drivers/net/ppp/ppp_generic.c b/drivers/net/ppp/ppp_generic.c index edfa15d2e795..486b4048850d 100644 --- a/drivers/net/ppp/ppp_generic.c +++ b/drivers/net/ppp/ppp_generic.c @@ -2024,14 +2024,22 @@ ppp_mp_reconstruct(struct ppp *ppp) continue; } if (PPP_MP_CB(p)->sequence != seq) { + u32 oldseq; /* Fragment `seq' is missing. If it is after minseq, it might arrive later, so stop here. */ if (seq_after(seq, minseq)) break; /* Fragment `seq' is lost, keep going. */ lost = 1; + oldseq = seq; seq = seq_before(minseq, PPP_MP_CB(p)->sequence)? minseq + 1: PPP_MP_CB(p)->sequence; + + if (ppp->debug & 1) + netdev_printk(KERN_DEBUG, ppp->dev, + "lost frag %u..%u\n", + oldseq, seq-1); + goto again; } @@ -2076,6 +2084,10 @@ ppp_mp_reconstruct(struct ppp *ppp) struct sk_buff *tmp2; skb_queue_reverse_walk_from_safe(list, p, tmp2) { + if (ppp->debug & 1) + netdev_printk(KERN_DEBUG, ppp->dev, + "discarding frag %u\n", + PPP_MP_CB(p)->sequence); __skb_unlink(p, list); kfree_skb(p); } @@ -2091,6 +2103,17 @@ ppp_mp_reconstruct(struct ppp *ppp) /* If we have discarded any fragments, signal a receive error. */ if (PPP_MP_CB(head)->sequence != ppp->nextseq) { + skb_queue_walk_safe(list, p, tmp) { + if (p == head) + break; + if (ppp->debug & 1) + netdev_printk(KERN_DEBUG, ppp->dev, + "discarding frag %u\n", + PPP_MP_CB(p)->sequence); + __skb_unlink(p, list); + kfree_skb(p); + } + if (ppp->debug & 1) netdev_printk(KERN_DEBUG, ppp->dev, " missed pkts %u..%u\n", -- 2.39.2