![Florian Westphal](/assets/img/avatar_default.png)
skb_gso_segment() has a 'features' argument representing offload features available to the output path. A few handlers, e.g. GRE, instead re-fetch the features of skb->dev and use those instead of the provided ones when handing encapsulation/tunnels. Depending on dev->hw_enc_features of the output device skb_gso_segment() can then return NULL even when the caller has disabled all GSO feature bits, as segmentation of inner header thinks device will take care of segmentation. This e.g. affects the tbf scheduler, which will silently drop GRE-encap GSO skbs that did not fit the remaining token quota as the segmentation does not work when device supports corresponding hw offload capabilities. Cc: Pravin B Shelar <pshelar@nicira.com> Signed-off-by: Florian Westphal <fw@strlen.de> Signed-off-by: David S. Miller <davem@davemloft.net>
317 lines
7.6 KiB
C
317 lines
7.6 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 "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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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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if (unlikely(skb_shinfo(skb)->gso_type &
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~(SKB_GSO_UDP |
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SKB_GSO_DODGY |
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SKB_GSO_TCP_ECN |
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SKB_GSO_GRE |
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SKB_GSO_GRE_CSUM |
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SKB_GSO_IPIP |
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SKB_GSO_SIT |
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SKB_GSO_UDP_TUNNEL |
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SKB_GSO_UDP_TUNNEL_CSUM |
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SKB_GSO_MPLS |
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SKB_GSO_TCPV6 |
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0)))
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goto out;
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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_SIT|SKB_GSO_IPIP))
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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(segs))
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goto out;
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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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ipv6h->payload_len = htons(skb->len - nhoff - sizeof(*ipv6h));
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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 != NULL)
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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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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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/* Clear flush_id, there's really no concept of ID in IPv6. */
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NAPI_GRO_CB(p)->flush_id = 0;
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}
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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 = 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 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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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 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 = 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 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 (udp_offload_init() < 0)
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pr_crit("%s: Cannot add UDP 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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return 0;
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}
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fs_initcall(ipv6_offload_init);
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