| /* |
| * IPV6 GSO/GRO offload support |
| * Linux INET6 implementation |
| * |
| * This program is free software; you can redistribute it and/or |
| * modify it under the terms of the GNU General Public License |
| * as published by the Free Software Foundation; either version |
| * 2 of the License, or (at your option) any later version. |
| * |
| * UDPv6 GSO support |
| */ |
| #include <linux/skbuff.h> |
| #include <linux/netdevice.h> |
| #include <net/protocol.h> |
| #include <net/ipv6.h> |
| #include <net/udp.h> |
| #include <net/ip6_checksum.h> |
| #include "ip6_offload.h" |
| |
| static struct sk_buff *udp6_ufo_fragment(struct sk_buff *skb, |
| netdev_features_t features) |
| { |
| struct sk_buff *segs = ERR_PTR(-EINVAL); |
| unsigned int mss; |
| unsigned int unfrag_ip6hlen, unfrag_len; |
| struct frag_hdr *fptr; |
| u8 *packet_start, *prevhdr; |
| u8 nexthdr; |
| u8 frag_hdr_sz = sizeof(struct frag_hdr); |
| __wsum csum; |
| int tnl_hlen; |
| int err; |
| |
| mss = skb_shinfo(skb)->gso_size; |
| if (unlikely(skb->len <= mss)) |
| goto out; |
| |
| if (skb->encapsulation && skb_shinfo(skb)->gso_type & |
| (SKB_GSO_UDP_TUNNEL|SKB_GSO_UDP_TUNNEL_CSUM)) |
| segs = skb_udp_tunnel_segment(skb, features, true); |
| else { |
| const struct ipv6hdr *ipv6h; |
| struct udphdr *uh; |
| |
| if (!pskb_may_pull(skb, sizeof(struct udphdr))) |
| goto out; |
| |
| /* Do software UFO. Complete and fill in the UDP checksum as HW cannot |
| * do checksum of UDP packets sent as multiple IP fragments. |
| */ |
| |
| uh = udp_hdr(skb); |
| ipv6h = ipv6_hdr(skb); |
| |
| uh->check = 0; |
| csum = skb_checksum(skb, 0, skb->len, 0); |
| uh->check = udp_v6_check(skb->len, &ipv6h->saddr, |
| &ipv6h->daddr, csum); |
| if (uh->check == 0) |
| uh->check = CSUM_MANGLED_0; |
| |
| skb->ip_summed = CHECKSUM_UNNECESSARY; |
| |
| /* If there is no outer header we can fake a checksum offload |
| * due to the fact that we have already done the checksum in |
| * software prior to segmenting the frame. |
| */ |
| if (!skb->encap_hdr_csum) |
| features |= NETIF_F_HW_CSUM; |
| |
| /* Check if there is enough headroom to insert fragment header. */ |
| tnl_hlen = skb_tnl_header_len(skb); |
| if (skb->mac_header < (tnl_hlen + frag_hdr_sz)) { |
| if (gso_pskb_expand_head(skb, tnl_hlen + frag_hdr_sz)) |
| goto out; |
| } |
| |
| /* Find the unfragmentable header and shift it left by frag_hdr_sz |
| * bytes to insert fragment header. |
| */ |
| err = ip6_find_1stfragopt(skb, &prevhdr); |
| if (err < 0) |
| return ERR_PTR(err); |
| unfrag_ip6hlen = err; |
| nexthdr = *prevhdr; |
| *prevhdr = NEXTHDR_FRAGMENT; |
| unfrag_len = (skb_network_header(skb) - skb_mac_header(skb)) + |
| unfrag_ip6hlen + tnl_hlen; |
| packet_start = (u8 *) skb->head + SKB_GSO_CB(skb)->mac_offset; |
| memmove(packet_start-frag_hdr_sz, packet_start, unfrag_len); |
| |
| SKB_GSO_CB(skb)->mac_offset -= frag_hdr_sz; |
| skb->mac_header -= frag_hdr_sz; |
| skb->network_header -= frag_hdr_sz; |
| |
| fptr = (struct frag_hdr *)(skb_network_header(skb) + unfrag_ip6hlen); |
| fptr->nexthdr = nexthdr; |
| fptr->reserved = 0; |
| fptr->identification = ipv6_proxy_select_ident(dev_net(skb->dev), skb); |
| |
| /* Fragment the skb. ipv6 header and the remaining fields of the |
| * fragment header are updated in ipv6_gso_segment() |
| */ |
| segs = skb_segment(skb, features); |
| } |
| |
| out: |
| return segs; |
| } |
| |
| static struct sk_buff **udp6_gro_receive(struct sk_buff **head, |
| struct sk_buff *skb) |
| { |
| struct udphdr *uh = udp_gro_udphdr(skb); |
| |
| if (unlikely(!uh)) |
| goto flush; |
| |
| /* Don't bother verifying checksum if we're going to flush anyway. */ |
| if (NAPI_GRO_CB(skb)->flush) |
| goto skip; |
| |
| if (skb_gro_checksum_validate_zero_check(skb, IPPROTO_UDP, uh->check, |
| ip6_gro_compute_pseudo)) |
| goto flush; |
| else if (uh->check) |
| skb_gro_checksum_try_convert(skb, IPPROTO_UDP, uh->check, |
| ip6_gro_compute_pseudo); |
| |
| skip: |
| NAPI_GRO_CB(skb)->is_ipv6 = 1; |
| return udp_gro_receive(head, skb, uh, udp6_lib_lookup_skb); |
| |
| flush: |
| NAPI_GRO_CB(skb)->flush = 1; |
| return NULL; |
| } |
| |
| static int udp6_gro_complete(struct sk_buff *skb, int nhoff) |
| { |
| const struct ipv6hdr *ipv6h = ipv6_hdr(skb); |
| struct udphdr *uh = (struct udphdr *)(skb->data + nhoff); |
| |
| if (uh->check) { |
| skb_shinfo(skb)->gso_type |= SKB_GSO_UDP_TUNNEL_CSUM; |
| uh->check = ~udp_v6_check(skb->len - nhoff, &ipv6h->saddr, |
| &ipv6h->daddr, 0); |
| } else { |
| skb_shinfo(skb)->gso_type |= SKB_GSO_UDP_TUNNEL; |
| } |
| |
| return udp_gro_complete(skb, nhoff, udp6_lib_lookup_skb); |
| } |
| |
| static const struct net_offload udpv6_offload = { |
| .callbacks = { |
| .gso_segment = udp6_ufo_fragment, |
| .gro_receive = udp6_gro_receive, |
| .gro_complete = udp6_gro_complete, |
| }, |
| }; |
| |
| int udpv6_offload_init(void) |
| { |
| return inet6_add_offload(&udpv6_offload, IPPROTO_UDP); |
| } |
| |
| int udpv6_offload_exit(void) |
| { |
| return inet6_del_offload(&udpv6_offload, IPPROTO_UDP); |
| } |