On 09/06/2012 01:40 PM, Nicolas Dichtel wrote:
dst stored in struct sctp_transport needs to be recalculated when ipsec policy are updated. We use flow_cache_genid for that. For example, if a SCTP connection is established and then an IPsec policy is set, the old SCTP flow will not be updated and thus will not use the new IPsec policy. Signed-off-by: Nicolas Dichtel <nicolas.dichtel@xxxxxxxxx>
why doesn't this need to be done for TCP? What makes SCTP special in this case?
ip_queue_xmit does an __sk_dst_check() which is essentially what sctp_transport_dst_check() does. That should determine if the currently cached route is valid or not.
Looks like sctp may need to change to using ip_route_output_ports() call as ip_route_output_key may not do all that is necessary -vlad
--- include/net/sctp/sctp.h | 3 ++- include/net/sctp/structs.h | 3 +++ net/sctp/ipv6.c | 1 + net/sctp/protocol.c | 1 + 4 files changed, 7 insertions(+), 1 deletion(-) diff --git a/include/net/sctp/sctp.h b/include/net/sctp/sctp.h index 9c6414f..3267246 100644 --- a/include/net/sctp/sctp.h +++ b/include/net/sctp/sctp.h @@ -712,7 +712,8 @@ static inline void sctp_v4_map_v6(union sctp_addr *addr) */ static inline struct dst_entry *sctp_transport_dst_check(struct sctp_transport *t) { - if (t->dst && !dst_check(t->dst, 0)) { + if ((t->dst && !dst_check(t->dst, 0)) || + (t->flow_cache_genid != atomic_read(&flow_cache_genid))) { dst_release(t->dst); t->dst = NULL; } diff --git a/include/net/sctp/structs.h b/include/net/sctp/structs.h index 0fef00f..9dab882 100644 --- a/include/net/sctp/structs.h +++ b/include/net/sctp/structs.h @@ -948,6 +948,9 @@ struct sctp_transport { /* 64-bit random number sent with heartbeat. */ __u64 hb_nonce; + + /* used to check validity of dst */ + __u32 flow_cache_genid; }; struct sctp_transport *sctp_transport_new(struct net *, const union sctp_addr *, diff --git a/net/sctp/ipv6.c b/net/sctp/ipv6.c index ea14cb4..2ed7410 100644 --- a/net/sctp/ipv6.c +++ b/net/sctp/ipv6.c @@ -349,6 +349,7 @@ out: struct rt6_info *rt; rt = (struct rt6_info *)dst; t->dst = dst; + t->flow_cache_genid = atomic_read(&flow_cache_genid); SCTP_DEBUG_PRINTK("rt6_dst:%pI6 rt6_src:%pI6\n", &rt->rt6i_dst.addr, &fl6->saddr); } else { diff --git a/net/sctp/protocol.c b/net/sctp/protocol.c index 2d51842..4795a1a 100644 --- a/net/sctp/protocol.c +++ b/net/sctp/protocol.c @@ -512,6 +512,7 @@ out_unlock: rcu_read_unlock(); out: t->dst = dst; + t->flow_cache_genid = atomic_read(&flow_cache_genid); if (dst) SCTP_DEBUG_PRINTK("rt_dst:%pI4, rt_src:%pI4\n", &fl4->daddr, &fl4->saddr);
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