diff options
Diffstat (limited to 'net/ipv4/gre_offload.c')
| -rw-r--r-- | net/ipv4/gre_offload.c | 160 |
1 files changed, 160 insertions, 0 deletions
diff --git a/net/ipv4/gre_offload.c b/net/ipv4/gre_offload.c index 9138cfb1014..746a7b10d43 100644 --- a/net/ipv4/gre_offload.c +++ b/net/ipv4/gre_offload.c @@ -116,10 +116,170 @@ out: return segs; } +/* Compute the whole skb csum in s/w and store it, then verify GRO csum + * starting from gro_offset. + */ +static __sum16 gro_skb_checksum(struct sk_buff *skb) +{ + __sum16 sum; + + skb->csum = skb_checksum(skb, 0, skb->len, 0); + NAPI_GRO_CB(skb)->csum = csum_sub(skb->csum, + csum_partial(skb->data, skb_gro_offset(skb), 0)); + sum = csum_fold(NAPI_GRO_CB(skb)->csum); + if (unlikely(skb->ip_summed == CHECKSUM_COMPLETE)) { + if (unlikely(!sum)) + netdev_rx_csum_fault(skb->dev); + } else + skb->ip_summed = CHECKSUM_COMPLETE; + + return sum; +} + +static struct sk_buff **gre_gro_receive(struct sk_buff **head, + struct sk_buff *skb) +{ + struct sk_buff **pp = NULL; + struct sk_buff *p; + const struct gre_base_hdr *greh; + unsigned int hlen, grehlen; + unsigned int off; + int flush = 1; + struct packet_offload *ptype; + __be16 type; + + off = skb_gro_offset(skb); + hlen = off + sizeof(*greh); + greh = skb_gro_header_fast(skb, off); + if (skb_gro_header_hard(skb, hlen)) { + greh = skb_gro_header_slow(skb, hlen, off); + if (unlikely(!greh)) + goto out; + } + + /* Only support version 0 and K (key), C (csum) flags. Note that + * although the support for the S (seq#) flag can be added easily + * for GRO, this is problematic for GSO hence can not be enabled + * here because a GRO pkt may end up in the forwarding path, thus + * requiring GSO support to break it up correctly. + */ + if ((greh->flags & ~(GRE_KEY|GRE_CSUM)) != 0) + goto out; + + type = greh->protocol; + + rcu_read_lock(); + ptype = gro_find_receive_by_type(type); + if (ptype == NULL) + goto out_unlock; + + grehlen = GRE_HEADER_SECTION; + + if (greh->flags & GRE_KEY) + grehlen += GRE_HEADER_SECTION; + + if (greh->flags & GRE_CSUM) + grehlen += GRE_HEADER_SECTION; + + hlen = off + grehlen; + if (skb_gro_header_hard(skb, hlen)) { + greh = skb_gro_header_slow(skb, hlen, off); + if (unlikely(!greh)) + goto out_unlock; + } + if (greh->flags & GRE_CSUM) { /* Need to verify GRE csum first */ + __sum16 csum = 0; + + if (skb->ip_summed == CHECKSUM_COMPLETE) + csum = csum_fold(NAPI_GRO_CB(skb)->csum); + /* Don't trust csum error calculated/reported by h/w */ + if (skb->ip_summed == CHECKSUM_NONE || csum != 0) + csum = gro_skb_checksum(skb); + + /* GRE CSUM is the 1's complement of the 1's complement sum + * of the GRE hdr plus payload so it should add up to 0xffff + * (and 0 after csum_fold()) just like the IPv4 hdr csum. + */ + if (csum) + goto out_unlock; + } + flush = 0; + + for (p = *head; p; p = p->next) { + const struct gre_base_hdr *greh2; + + if (!NAPI_GRO_CB(p)->same_flow) + continue; + + /* The following checks are needed to ensure only pkts + * from the same tunnel are considered for aggregation. + * The criteria for "the same tunnel" includes: + * 1) same version (we only support version 0 here) + * 2) same protocol (we only support ETH_P_IP for now) + * 3) same set of flags + * 4) same key if the key field is present. + */ + greh2 = (struct gre_base_hdr *)(p->data + off); + + if (greh2->flags != greh->flags || + greh2->protocol != greh->protocol) { + NAPI_GRO_CB(p)->same_flow = 0; + continue; + } + if (greh->flags & GRE_KEY) { + /* compare keys */ + if (*(__be32 *)(greh2+1) != *(__be32 *)(greh+1)) { + NAPI_GRO_CB(p)->same_flow = 0; + continue; + } + } + } + + skb_gro_pull(skb, grehlen); + + /* Adjusted NAPI_GRO_CB(skb)->csum after skb_gro_pull()*/ + skb_gro_postpull_rcsum(skb, greh, grehlen); + + pp = ptype->callbacks.gro_receive(head, skb); + +out_unlock: + rcu_read_unlock(); +out: + NAPI_GRO_CB(skb)->flush |= flush; + + return pp; +} + +int gre_gro_complete(struct sk_buff *skb, int nhoff) +{ + struct gre_base_hdr *greh = (struct gre_base_hdr *)(skb->data + nhoff); + struct packet_offload *ptype; + unsigned int grehlen = sizeof(*greh); + int err = -ENOENT; + __be16 type; + + type = greh->protocol; + if (greh->flags & GRE_KEY) + grehlen += GRE_HEADER_SECTION; + + if (greh->flags & GRE_CSUM) + grehlen += GRE_HEADER_SECTION; + + rcu_read_lock(); + ptype = gro_find_complete_by_type(type); + if (ptype != NULL) + err = ptype->callbacks.gro_complete(skb, nhoff + grehlen); + + rcu_read_unlock(); + return err; +} + static const struct net_offload gre_offload = { .callbacks = { .gso_send_check = gre_gso_send_check, .gso_segment = gre_gso_segment, + .gro_receive = gre_gro_receive, + .gro_complete = gre_gro_complete, }, }; |