user/sven/linux.git/include/linux/skbuff.h, branch v3.12.29

net: ip, ipv6: handle gso skbs in forwarding path

2014-02-26T09:22:53Z

commit fe6cc55f3a9a053482a76f5a6b2257cee51b4663 upstream. Marcelo Ricardo Leitner reported problems when the forwarding link path has a lower mtu than the incoming one if the inbound interface supports GRO. Given: Host R1 R2 Host sends tcp stream which is routed via R1 and R2. R1 performs GRO. In this case, the kernel will fail to send ICMP fragmentation needed messages (or pkt too big for ipv6), as GSO packets currently bypass dstmtu checks in forward path. Instead, Linux tries to send out packets exceeding the mtu. When locking route MTU on Host (i.e., no ipv4 DF bit set), R1 does not fragment the packets when forwarding, and again tries to send out packets exceeding R1-R2 link mtu. This alters the forwarding dstmtu checks to take the individual gso segment lengths into account. For ipv6, we send out pkt too big error for gso if the individual segments are too big. For ipv4, we either send icmp fragmentation needed, or, if the DF bit is not set, perform software segmentation and let the output path create fragments when the packet is leaving the machine. It is not 100% correct as the error message will contain the headers of the GRO skb instead of the original/segmented one, but it seems to work fine in my (limited) tests. Eric Dumazet suggested to simply shrink mss via ->gso_size to avoid sofware segmentation. However it turns out that skb_segment() assumes skb nr_frags is related to mss size so we would BUG there. I don't want to mess with it considering Herbert and Eric disagree on what the correct behavior should be. Hannes Frederic Sowa notes that when we would shrink gso_size skb_segment would then also need to deal with the case where SKB_MAX_FRAGS would be exceeded. This uses sofware segmentation in the forward path when we hit ipv4 non-DF packets and the outgoing link mtu is too small. Its not perfect, but given the lack of bug reports wrt. GRO fwd being broken this is a rare case anyway. Also its not like this could not be improved later once the dust settles. Acked-by: Herbert Xu Reported-by: Marcelo Ricardo Leitner Signed-off-by: Florian Westphal Signed-off-by: David S. Miller Signed-off-by: Jiri Slaby

net: add and use skb_gso_transport_seglen()

2014-02-26T09:22:53Z

commit de960aa9ab4decc3304959f69533eef64d05d8e8 upstream. This moves part of Eric Dumazets skb_gso_seglen helper from tbf sched to skbuff core so it may be reused by upcoming ip forwarding path patch. Signed-off-by: Florian Westphal Acked-by: Eric Dumazet Signed-off-by: David S. Miller Signed-off-by: Jiri Slaby

ip_gre: fix msg_name parsing for recvfrom/recvmsg

2014-01-15T23:31:35Z

[ Upstream commit 0e3da5bb8da45890b1dc413404e0f978ab71173e ] ipgre_header_parse() needs to parse the tunnel's ip header and it uses mac_header to locate the iphdr. This got broken when gre tunneling was refactored as mac_header is no longer updated to point to iphdr. Introduce skb_pop_mac_header() helper to do the mac_header assignment and use it in ipgre_rcv() to fix msg_name parsing. Bug introduced in commit c54419321455 (GRE: Refactor GRE tunneling code.) Cc: Pravin B Shelar Signed-off-by: Timo Teräs Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman

netfilter: push reasm skb through instead of original frag skbs

2013-12-08T15:29:13Z

[ Upstream commit 6aafeef03b9d9ecf255f3a80ed85ee070260e1ae ] Pushing original fragments through causes several problems. For example for matching, frags may not be matched correctly. Take following example: On HOSTA do: ip6tables -I INPUT -p icmpv6 -j DROP ip6tables -I INPUT -p icmpv6 -m icmp6 --icmpv6-type 128 -j ACCEPT and on HOSTB you do: ping6 HOSTA -s2000 (MTU is 1500) Incoming echo requests will be filtered out on HOSTA. This issue does not occur with smaller packets than MTU (where fragmentation does not happen) As was discussed previously, the only correct solution seems to be to use reassembled skb instead of separete frags. Doing this has positive side effects in reducing sk_buff by one pointer (nfct_reasm) and also the reams dances in ipvs and conntrack can be removed. Future plan is to remove net/ipv6/netfilter/nf_conntrack_reasm.c entirely and use code in net/ipv6/reassembly.c instead. Signed-off-by: Jiri Pirko Acked-by: Julian Anastasov Signed-off-by: Marcelo Ricardo Leitner Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman

skbuff: size of hole is wrong in a comment

2013-10-01T05:32:39Z

Since commit c93bdd0e03e8 ("netvm: allow skb allocation to use PFMEMALLOC reserves"), hole size is one bit less than what is written in the comment. Signed-off-by: Nicolas Dichtel Signed-off-by: David S. Miller

skb: allow skb_scrub_packet() to be used by tunnels

2013-09-04T04:27:25Z

This function was only used when a packet was sent to another netns. Now, it can also be used after tunnel encapsulation or decapsulation. Only skb_orphan() should not be done when a packet is not crossing netns. Signed-off-by: Nicolas Dichtel Signed-off-by: David S. Miller

net: fix comment typo for __skb_alloc_pages()

2013-09-04T02:17:40Z

The name of the function in the comment is __skb_alloc_page() while we are actually commenting __skb_alloc_pages(). Fix this typo and make it a valid kernel doc comment. Signed-off-by: Florian Fainelli Signed-off-by: David S. Miller

net: move zerocopy_sg_from_iovec() to net/core/datagram.c

2013-08-07T23:52:34Z

To let it be reused and reduce code duplication. Also document this function. Signed-off-by: Jason Wang Signed-off-by: David S. Miller

Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net

2013-08-04T04:36:46Z

Merge net into net-next to setup some infrastructure Eric Dumazet needs for usbnet changes. Signed-off-by: David S. Miller

net: rename CONFIG_NET_LL_RX_POLL to CONFIG_NET_RX_BUSY_POLL

2013-08-01T22:11:17Z

Eliezer renames several *ll_poll to *busy_poll, but forgets CONFIG_NET_LL_RX_POLL, so in case of confusion, rename it too. Cc: Eliezer Tamir Cc: David S. Miller Signed-off-by: Cong Wang Signed-off-by: David S. Miller