![Herbert Xu](/assets/img/avatar_default.png)
The GRO fast path caches the frag0 address. This address becomes
invalid if frag0 is modified by pskb_may_pull or its variants.
So whenever that happens we must disable the frag0 optimization.
This is usually done through the combination of gro_header_hard
and gro_header_slow, however, the IPv6 extension header path did
the pulling directly and would continue to use the GRO fast path
incorrectly.
This patch fixes it by disabling the fast path when we enter the
IPv6 extension header path.
Fixes: 78a478d0ef
("gro: Inline skb_gro_header and cache frag0 virtual address")
Reported-by: Slava Shwartsman <slavash@mellanox.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
387 lines
9.3 KiB
C
387 lines
9.3 KiB
C
/*
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* IPV6 GSO/GRO offload support
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* Linux INET6 implementation
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License
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* as published by the Free Software Foundation; either version
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* 2 of the License, or (at your option) any later version.
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*/
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#include <linux/kernel.h>
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#include <linux/socket.h>
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#include <linux/netdevice.h>
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#include <linux/skbuff.h>
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#include <linux/printk.h>
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#include <net/protocol.h>
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#include <net/ipv6.h>
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#include <net/inet_common.h>
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#include "ip6_offload.h"
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static int ipv6_gso_pull_exthdrs(struct sk_buff *skb, int proto)
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{
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const struct net_offload *ops = NULL;
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for (;;) {
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struct ipv6_opt_hdr *opth;
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int len;
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if (proto != NEXTHDR_HOP) {
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ops = rcu_dereference(inet6_offloads[proto]);
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if (unlikely(!ops))
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break;
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if (!(ops->flags & INET6_PROTO_GSO_EXTHDR))
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break;
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}
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if (unlikely(!pskb_may_pull(skb, 8)))
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break;
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opth = (void *)skb->data;
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len = ipv6_optlen(opth);
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if (unlikely(!pskb_may_pull(skb, len)))
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break;
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opth = (void *)skb->data;
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proto = opth->nexthdr;
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__skb_pull(skb, len);
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}
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return proto;
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}
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static struct sk_buff *ipv6_gso_segment(struct sk_buff *skb,
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netdev_features_t features)
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{
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struct sk_buff *segs = ERR_PTR(-EINVAL);
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struct ipv6hdr *ipv6h;
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const struct net_offload *ops;
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int proto;
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struct frag_hdr *fptr;
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unsigned int unfrag_ip6hlen;
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unsigned int payload_len;
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u8 *prevhdr;
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int offset = 0;
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bool encap, udpfrag;
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int nhoff;
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bool gso_partial;
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skb_reset_network_header(skb);
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nhoff = skb_network_header(skb) - skb_mac_header(skb);
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if (unlikely(!pskb_may_pull(skb, sizeof(*ipv6h))))
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goto out;
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encap = SKB_GSO_CB(skb)->encap_level > 0;
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if (encap)
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features &= skb->dev->hw_enc_features;
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SKB_GSO_CB(skb)->encap_level += sizeof(*ipv6h);
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ipv6h = ipv6_hdr(skb);
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__skb_pull(skb, sizeof(*ipv6h));
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segs = ERR_PTR(-EPROTONOSUPPORT);
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proto = ipv6_gso_pull_exthdrs(skb, ipv6h->nexthdr);
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if (skb->encapsulation &&
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skb_shinfo(skb)->gso_type & (SKB_GSO_IPXIP4 | SKB_GSO_IPXIP6))
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udpfrag = proto == IPPROTO_UDP && encap;
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else
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udpfrag = proto == IPPROTO_UDP && !skb->encapsulation;
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ops = rcu_dereference(inet6_offloads[proto]);
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if (likely(ops && ops->callbacks.gso_segment)) {
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skb_reset_transport_header(skb);
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segs = ops->callbacks.gso_segment(skb, features);
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}
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if (IS_ERR_OR_NULL(segs))
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goto out;
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gso_partial = !!(skb_shinfo(segs)->gso_type & SKB_GSO_PARTIAL);
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for (skb = segs; skb; skb = skb->next) {
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ipv6h = (struct ipv6hdr *)(skb_mac_header(skb) + nhoff);
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if (gso_partial)
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payload_len = skb_shinfo(skb)->gso_size +
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SKB_GSO_CB(skb)->data_offset +
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skb->head - (unsigned char *)(ipv6h + 1);
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else
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payload_len = skb->len - nhoff - sizeof(*ipv6h);
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ipv6h->payload_len = htons(payload_len);
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skb->network_header = (u8 *)ipv6h - skb->head;
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if (udpfrag) {
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unfrag_ip6hlen = ip6_find_1stfragopt(skb, &prevhdr);
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fptr = (struct frag_hdr *)((u8 *)ipv6h + unfrag_ip6hlen);
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fptr->frag_off = htons(offset);
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if (skb->next)
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fptr->frag_off |= htons(IP6_MF);
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offset += (ntohs(ipv6h->payload_len) -
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sizeof(struct frag_hdr));
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}
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if (encap)
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skb_reset_inner_headers(skb);
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}
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out:
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return segs;
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}
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/* Return the total length of all the extension hdrs, following the same
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* logic in ipv6_gso_pull_exthdrs() when parsing ext-hdrs.
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*/
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static int ipv6_exthdrs_len(struct ipv6hdr *iph,
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const struct net_offload **opps)
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{
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struct ipv6_opt_hdr *opth = (void *)iph;
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int len = 0, proto, optlen = sizeof(*iph);
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proto = iph->nexthdr;
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for (;;) {
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if (proto != NEXTHDR_HOP) {
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*opps = rcu_dereference(inet6_offloads[proto]);
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if (unlikely(!(*opps)))
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break;
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if (!((*opps)->flags & INET6_PROTO_GSO_EXTHDR))
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break;
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}
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opth = (void *)opth + optlen;
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optlen = ipv6_optlen(opth);
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len += optlen;
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proto = opth->nexthdr;
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}
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return len;
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}
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static struct sk_buff **ipv6_gro_receive(struct sk_buff **head,
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struct sk_buff *skb)
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{
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const struct net_offload *ops;
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struct sk_buff **pp = NULL;
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struct sk_buff *p;
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struct ipv6hdr *iph;
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unsigned int nlen;
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unsigned int hlen;
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unsigned int off;
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u16 flush = 1;
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int proto;
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off = skb_gro_offset(skb);
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hlen = off + sizeof(*iph);
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iph = skb_gro_header_fast(skb, off);
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if (skb_gro_header_hard(skb, hlen)) {
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iph = skb_gro_header_slow(skb, hlen, off);
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if (unlikely(!iph))
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goto out;
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}
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skb_set_network_header(skb, off);
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skb_gro_pull(skb, sizeof(*iph));
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skb_set_transport_header(skb, skb_gro_offset(skb));
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flush += ntohs(iph->payload_len) != skb_gro_len(skb);
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rcu_read_lock();
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proto = iph->nexthdr;
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ops = rcu_dereference(inet6_offloads[proto]);
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if (!ops || !ops->callbacks.gro_receive) {
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__pskb_pull(skb, skb_gro_offset(skb));
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skb_gro_frag0_invalidate(skb);
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proto = ipv6_gso_pull_exthdrs(skb, proto);
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skb_gro_pull(skb, -skb_transport_offset(skb));
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skb_reset_transport_header(skb);
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__skb_push(skb, skb_gro_offset(skb));
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ops = rcu_dereference(inet6_offloads[proto]);
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if (!ops || !ops->callbacks.gro_receive)
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goto out_unlock;
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iph = ipv6_hdr(skb);
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}
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NAPI_GRO_CB(skb)->proto = proto;
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flush--;
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nlen = skb_network_header_len(skb);
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for (p = *head; p; p = p->next) {
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const struct ipv6hdr *iph2;
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__be32 first_word; /* <Version:4><Traffic_Class:8><Flow_Label:20> */
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if (!NAPI_GRO_CB(p)->same_flow)
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continue;
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iph2 = (struct ipv6hdr *)(p->data + off);
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first_word = *(__be32 *)iph ^ *(__be32 *)iph2;
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/* All fields must match except length and Traffic Class.
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* XXX skbs on the gro_list have all been parsed and pulled
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* already so we don't need to compare nlen
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* (nlen != (sizeof(*iph2) + ipv6_exthdrs_len(iph2, &ops)))
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* memcmp() alone below is suffcient, right?
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*/
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if ((first_word & htonl(0xF00FFFFF)) ||
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memcmp(&iph->nexthdr, &iph2->nexthdr,
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nlen - offsetof(struct ipv6hdr, nexthdr))) {
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NAPI_GRO_CB(p)->same_flow = 0;
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continue;
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}
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/* flush if Traffic Class fields are different */
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NAPI_GRO_CB(p)->flush |= !!(first_word & htonl(0x0FF00000));
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NAPI_GRO_CB(p)->flush |= flush;
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/* If the previous IP ID value was based on an atomic
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* datagram we can overwrite the value and ignore it.
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*/
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if (NAPI_GRO_CB(skb)->is_atomic)
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NAPI_GRO_CB(p)->flush_id = 0;
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}
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NAPI_GRO_CB(skb)->is_atomic = true;
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NAPI_GRO_CB(skb)->flush |= flush;
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skb_gro_postpull_rcsum(skb, iph, nlen);
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pp = call_gro_receive(ops->callbacks.gro_receive, head, skb);
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out_unlock:
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rcu_read_unlock();
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out:
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NAPI_GRO_CB(skb)->flush |= flush;
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return pp;
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}
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static struct sk_buff **sit_ip6ip6_gro_receive(struct sk_buff **head,
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struct sk_buff *skb)
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{
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/* Common GRO receive for SIT and IP6IP6 */
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if (NAPI_GRO_CB(skb)->encap_mark) {
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NAPI_GRO_CB(skb)->flush = 1;
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return NULL;
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}
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NAPI_GRO_CB(skb)->encap_mark = 1;
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return ipv6_gro_receive(head, skb);
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}
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static struct sk_buff **ip4ip6_gro_receive(struct sk_buff **head,
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struct sk_buff *skb)
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{
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/* Common GRO receive for SIT and IP6IP6 */
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if (NAPI_GRO_CB(skb)->encap_mark) {
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NAPI_GRO_CB(skb)->flush = 1;
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return NULL;
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}
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NAPI_GRO_CB(skb)->encap_mark = 1;
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return inet_gro_receive(head, skb);
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}
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static int ipv6_gro_complete(struct sk_buff *skb, int nhoff)
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{
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const struct net_offload *ops;
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struct ipv6hdr *iph = (struct ipv6hdr *)(skb->data + nhoff);
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int err = -ENOSYS;
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if (skb->encapsulation)
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skb_set_inner_network_header(skb, nhoff);
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iph->payload_len = htons(skb->len - nhoff - sizeof(*iph));
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rcu_read_lock();
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nhoff += sizeof(*iph) + ipv6_exthdrs_len(iph, &ops);
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if (WARN_ON(!ops || !ops->callbacks.gro_complete))
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goto out_unlock;
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err = ops->callbacks.gro_complete(skb, nhoff);
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out_unlock:
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rcu_read_unlock();
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return err;
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}
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static int sit_gro_complete(struct sk_buff *skb, int nhoff)
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{
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skb->encapsulation = 1;
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skb_shinfo(skb)->gso_type |= SKB_GSO_IPXIP4;
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return ipv6_gro_complete(skb, nhoff);
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}
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static int ip6ip6_gro_complete(struct sk_buff *skb, int nhoff)
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{
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skb->encapsulation = 1;
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skb_shinfo(skb)->gso_type |= SKB_GSO_IPXIP6;
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return ipv6_gro_complete(skb, nhoff);
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}
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static int ip4ip6_gro_complete(struct sk_buff *skb, int nhoff)
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{
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skb->encapsulation = 1;
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skb_shinfo(skb)->gso_type |= SKB_GSO_IPXIP6;
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return inet_gro_complete(skb, nhoff);
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}
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static struct packet_offload ipv6_packet_offload __read_mostly = {
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.type = cpu_to_be16(ETH_P_IPV6),
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.callbacks = {
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.gso_segment = ipv6_gso_segment,
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.gro_receive = ipv6_gro_receive,
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.gro_complete = ipv6_gro_complete,
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},
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};
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static const struct net_offload sit_offload = {
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.callbacks = {
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.gso_segment = ipv6_gso_segment,
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.gro_receive = sit_ip6ip6_gro_receive,
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.gro_complete = sit_gro_complete,
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},
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};
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static const struct net_offload ip4ip6_offload = {
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.callbacks = {
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.gso_segment = inet_gso_segment,
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.gro_receive = ip4ip6_gro_receive,
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.gro_complete = ip4ip6_gro_complete,
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},
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};
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static const struct net_offload ip6ip6_offload = {
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.callbacks = {
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.gso_segment = ipv6_gso_segment,
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.gro_receive = sit_ip6ip6_gro_receive,
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.gro_complete = ip6ip6_gro_complete,
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},
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};
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static int __init ipv6_offload_init(void)
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{
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if (tcpv6_offload_init() < 0)
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pr_crit("%s: Cannot add TCP protocol offload\n", __func__);
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if (ipv6_exthdrs_offload_init() < 0)
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pr_crit("%s: Cannot add EXTHDRS protocol offload\n", __func__);
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dev_add_offload(&ipv6_packet_offload);
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inet_add_offload(&sit_offload, IPPROTO_IPV6);
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inet6_add_offload(&ip6ip6_offload, IPPROTO_IPV6);
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inet6_add_offload(&ip4ip6_offload, IPPROTO_IPIP);
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return 0;
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}
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fs_initcall(ipv6_offload_init);
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