From f880374c2fe37aad3fa62253a4bc125d7a933aad Mon Sep 17 00:00:00 2001 From: Herbert Xu Date: Sun, 3 Aug 2008 21:15:08 -0700 Subject: sctp: Drop ipfargok in sctp_xmit function The ipfragok flag controls whether the packet may be fragmented either on the local host on beyond. The latter is only valid on IPv4. In fact, we never want to do the latter even on IPv4 when PMTU is enabled. This is because even though we can't fragment packets within SCTP due to the prtocol's inherent faults, we can still fragment it at IP layer. By setting the DF bit we will improve the PMTU process. RFC 2960 only says that we SHOULD clear the DF bit in this case, so we're compliant even if we set the DF bit. In fact RFC 4960 no longer has this statement. Once we make this change, we only need to control the local fragmentation. There is already a bit in the skb which controls that, local_df. So this patch sets that instead of using the ipfragok argument. The only complication is that there isn't a struct sock object per transport, so for IPv4 we have to resort to changing the pmtudisc field for every packet. This should be safe though as the protocol is single-threaded. Note that after this patch we can remove ipfragok from the rest of the stack too. Signed-off-by: Herbert Xu Signed-off-by: David S. Miller --- net/sctp/ipv6.c | 8 +++++--- 1 file changed, 5 insertions(+), 3 deletions(-) (limited to 'net/sctp/ipv6.c') diff --git a/net/sctp/ipv6.c b/net/sctp/ipv6.c index a238d6834b3..483a01d0740 100644 --- a/net/sctp/ipv6.c +++ b/net/sctp/ipv6.c @@ -195,8 +195,7 @@ out: } /* Based on tcp_v6_xmit() in tcp_ipv6.c. */ -static int sctp_v6_xmit(struct sk_buff *skb, struct sctp_transport *transport, - int ipfragok) +static int sctp_v6_xmit(struct sk_buff *skb, struct sctp_transport *transport) { struct sock *sk = skb->sk; struct ipv6_pinfo *np = inet6_sk(sk); @@ -231,7 +230,10 @@ static int sctp_v6_xmit(struct sk_buff *skb, struct sctp_transport *transport, SCTP_INC_STATS(SCTP_MIB_OUTSCTPPACKS); - return ip6_xmit(sk, skb, &fl, np->opt, ipfragok); + if (!(transport->param_flags & SPP_PMTUD_ENABLE)) + skb->local_df = 1; + + return ip6_xmit(sk, skb, &fl, np->opt, 0); } /* Returns the dst cache entry for the given source and destination ip -- cgit v1.2.3