| 1 | /* |
| 2 | * IPV6 GSO/GRO offload support |
| 3 | * Linux INET6 implementation |
| 4 | * |
| 5 | * This program is free software; you can redistribute it and/or |
| 6 | * modify it under the terms of the GNU General Public License |
| 7 | * as published by the Free Software Foundation; either version |
| 8 | * 2 of the License, or (at your option) any later version. |
| 9 | * |
| 10 | * UDPv6 GSO support |
| 11 | */ |
| 12 | #include <linux/skbuff.h> |
| 13 | #include <linux/netdevice.h> |
| 14 | #include <net/protocol.h> |
| 15 | #include <net/ipv6.h> |
| 16 | #include <net/udp.h> |
| 17 | #include <net/ip6_checksum.h> |
| 18 | #include "ip6_offload.h" |
| 19 | |
| 20 | static struct sk_buff *udp6_ufo_fragment(struct sk_buff *skb, |
| 21 | netdev_features_t features) |
| 22 | { |
| 23 | struct sk_buff *segs = ERR_PTR(-EINVAL); |
| 24 | unsigned int mss; |
| 25 | unsigned int unfrag_ip6hlen, unfrag_len; |
| 26 | struct frag_hdr *fptr; |
| 27 | u8 *packet_start, *prevhdr; |
| 28 | u8 nexthdr; |
| 29 | u8 frag_hdr_sz = sizeof(struct frag_hdr); |
| 30 | __wsum csum; |
| 31 | int tnl_hlen; |
| 32 | |
| 33 | mss = skb_shinfo(skb)->gso_size; |
| 34 | if (unlikely(skb->len <= mss)) |
| 35 | goto out; |
| 36 | |
| 37 | if (skb_gso_ok(skb, features | NETIF_F_GSO_ROBUST)) { |
| 38 | /* Packet is from an untrusted source, reset gso_segs. */ |
| 39 | |
| 40 | skb_shinfo(skb)->gso_segs = DIV_ROUND_UP(skb->len, mss); |
| 41 | |
| 42 | /* Set the IPv6 fragment id if not set yet */ |
| 43 | if (!skb_shinfo(skb)->ip6_frag_id) |
| 44 | ipv6_proxy_select_ident(dev_net(skb->dev), skb); |
| 45 | |
| 46 | segs = NULL; |
| 47 | goto out; |
| 48 | } |
| 49 | |
| 50 | if (skb->encapsulation && skb_shinfo(skb)->gso_type & |
| 51 | (SKB_GSO_UDP_TUNNEL|SKB_GSO_UDP_TUNNEL_CSUM)) |
| 52 | segs = skb_udp_tunnel_segment(skb, features, true); |
| 53 | else { |
| 54 | const struct ipv6hdr *ipv6h; |
| 55 | struct udphdr *uh; |
| 56 | |
| 57 | if (!pskb_may_pull(skb, sizeof(struct udphdr))) |
| 58 | goto out; |
| 59 | |
| 60 | /* Do software UFO. Complete and fill in the UDP checksum as HW cannot |
| 61 | * do checksum of UDP packets sent as multiple IP fragments. |
| 62 | */ |
| 63 | |
| 64 | uh = udp_hdr(skb); |
| 65 | ipv6h = ipv6_hdr(skb); |
| 66 | |
| 67 | uh->check = 0; |
| 68 | csum = skb_checksum(skb, 0, skb->len, 0); |
| 69 | uh->check = udp_v6_check(skb->len, &ipv6h->saddr, |
| 70 | &ipv6h->daddr, csum); |
| 71 | if (uh->check == 0) |
| 72 | uh->check = CSUM_MANGLED_0; |
| 73 | |
| 74 | skb->ip_summed = CHECKSUM_NONE; |
| 75 | |
| 76 | /* If there is no outer header we can fake a checksum offload |
| 77 | * due to the fact that we have already done the checksum in |
| 78 | * software prior to segmenting the frame. |
| 79 | */ |
| 80 | if (!skb->encap_hdr_csum) |
| 81 | features |= NETIF_F_HW_CSUM; |
| 82 | |
| 83 | /* Check if there is enough headroom to insert fragment header. */ |
| 84 | tnl_hlen = skb_tnl_header_len(skb); |
| 85 | if (skb->mac_header < (tnl_hlen + frag_hdr_sz)) { |
| 86 | if (gso_pskb_expand_head(skb, tnl_hlen + frag_hdr_sz)) |
| 87 | goto out; |
| 88 | } |
| 89 | |
| 90 | /* Find the unfragmentable header and shift it left by frag_hdr_sz |
| 91 | * bytes to insert fragment header. |
| 92 | */ |
| 93 | unfrag_ip6hlen = ip6_find_1stfragopt(skb, &prevhdr); |
| 94 | nexthdr = *prevhdr; |
| 95 | *prevhdr = NEXTHDR_FRAGMENT; |
| 96 | unfrag_len = (skb_network_header(skb) - skb_mac_header(skb)) + |
| 97 | unfrag_ip6hlen + tnl_hlen; |
| 98 | packet_start = (u8 *) skb->head + SKB_GSO_CB(skb)->mac_offset; |
| 99 | memmove(packet_start-frag_hdr_sz, packet_start, unfrag_len); |
| 100 | |
| 101 | SKB_GSO_CB(skb)->mac_offset -= frag_hdr_sz; |
| 102 | skb->mac_header -= frag_hdr_sz; |
| 103 | skb->network_header -= frag_hdr_sz; |
| 104 | |
| 105 | fptr = (struct frag_hdr *)(skb_network_header(skb) + unfrag_ip6hlen); |
| 106 | fptr->nexthdr = nexthdr; |
| 107 | fptr->reserved = 0; |
| 108 | if (!skb_shinfo(skb)->ip6_frag_id) |
| 109 | ipv6_proxy_select_ident(dev_net(skb->dev), skb); |
| 110 | fptr->identification = skb_shinfo(skb)->ip6_frag_id; |
| 111 | |
| 112 | /* Fragment the skb. ipv6 header and the remaining fields of the |
| 113 | * fragment header are updated in ipv6_gso_segment() |
| 114 | */ |
| 115 | segs = skb_segment(skb, features); |
| 116 | } |
| 117 | |
| 118 | out: |
| 119 | return segs; |
| 120 | } |
| 121 | |
| 122 | static struct sk_buff **udp6_gro_receive(struct sk_buff **head, |
| 123 | struct sk_buff *skb) |
| 124 | { |
| 125 | struct udphdr *uh = udp_gro_udphdr(skb); |
| 126 | |
| 127 | if (unlikely(!uh)) |
| 128 | goto flush; |
| 129 | |
| 130 | /* Don't bother verifying checksum if we're going to flush anyway. */ |
| 131 | if (NAPI_GRO_CB(skb)->flush) |
| 132 | goto skip; |
| 133 | |
| 134 | if (skb_gro_checksum_validate_zero_check(skb, IPPROTO_UDP, uh->check, |
| 135 | ip6_gro_compute_pseudo)) |
| 136 | goto flush; |
| 137 | else if (uh->check) |
| 138 | skb_gro_checksum_try_convert(skb, IPPROTO_UDP, uh->check, |
| 139 | ip6_gro_compute_pseudo); |
| 140 | |
| 141 | skip: |
| 142 | NAPI_GRO_CB(skb)->is_ipv6 = 1; |
| 143 | return udp_gro_receive(head, skb, uh, udp6_lib_lookup_skb); |
| 144 | |
| 145 | flush: |
| 146 | NAPI_GRO_CB(skb)->flush = 1; |
| 147 | return NULL; |
| 148 | } |
| 149 | |
| 150 | static int udp6_gro_complete(struct sk_buff *skb, int nhoff) |
| 151 | { |
| 152 | const struct ipv6hdr *ipv6h = ipv6_hdr(skb); |
| 153 | struct udphdr *uh = (struct udphdr *)(skb->data + nhoff); |
| 154 | |
| 155 | if (uh->check) { |
| 156 | skb_shinfo(skb)->gso_type |= SKB_GSO_UDP_TUNNEL_CSUM; |
| 157 | uh->check = ~udp_v6_check(skb->len - nhoff, &ipv6h->saddr, |
| 158 | &ipv6h->daddr, 0); |
| 159 | } else { |
| 160 | skb_shinfo(skb)->gso_type |= SKB_GSO_UDP_TUNNEL; |
| 161 | } |
| 162 | |
| 163 | return udp_gro_complete(skb, nhoff, udp6_lib_lookup_skb); |
| 164 | } |
| 165 | |
| 166 | static const struct net_offload udpv6_offload = { |
| 167 | .callbacks = { |
| 168 | .gso_segment = udp6_ufo_fragment, |
| 169 | .gro_receive = udp6_gro_receive, |
| 170 | .gro_complete = udp6_gro_complete, |
| 171 | }, |
| 172 | }; |
| 173 | |
| 174 | int udpv6_offload_init(void) |
| 175 | { |
| 176 | return inet6_add_offload(&udpv6_offload, IPPROTO_UDP); |
| 177 | } |
| 178 | |
| 179 | int udpv6_offload_exit(void) |
| 180 | { |
| 181 | return inet6_del_offload(&udpv6_offload, IPPROTO_UDP); |
| 182 | } |