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 11 #include <linux/kernel.h> 12 #include <linux/socket.h> 13 #include <linux/netdevice.h> 14 #include <linux/skbuff.h> 15 #include <linux/printk.h> 16 17 #include <net/protocol.h> 18 #include <net/ipv6.h> 19 20 #include "ip6_offload.h" 21 22 static int ipv6_gso_pull_exthdrs(struct sk_buff *skb, int proto) 23 { 24 const struct net_offload *ops = NULL; 25 26 for (;;) { 27 struct ipv6_opt_hdr *opth; 28 int len; 29 30 if (proto != NEXTHDR_HOP) { 31 ops = rcu_dereference(inet6_offloads[proto]); 32 33 if (unlikely(!ops)) 34 break; 35 36 if (!(ops->flags & INET6_PROTO_GSO_EXTHDR)) 37 break; 38 } 39 40 if (unlikely(!pskb_may_pull(skb, 8))) 41 break; 42 43 opth = (void *)skb->data; 44 len = ipv6_optlen(opth); 45 46 if (unlikely(!pskb_may_pull(skb, len))) 47 break; 48 49 opth = (void *)skb->data; 50 proto = opth->nexthdr; 51 __skb_pull(skb, len); 52 } 53 54 return proto; 55 } 56 57 static struct sk_buff *ipv6_gso_segment(struct sk_buff *skb, 58 netdev_features_t features) 59 { 60 struct sk_buff *segs = ERR_PTR(-EINVAL); 61 struct ipv6hdr *ipv6h; 62 const struct net_offload *ops; 63 int proto; 64 struct frag_hdr *fptr; 65 unsigned int unfrag_ip6hlen; 66 u8 *prevhdr; 67 int offset = 0; 68 bool encap, udpfrag; 69 int nhoff; 70 71 if (unlikely(skb_shinfo(skb)->gso_type & 72 ~(SKB_GSO_TCPV4 | 73 SKB_GSO_UDP | 74 SKB_GSO_DODGY | 75 SKB_GSO_TCP_ECN | 76 SKB_GSO_GRE | 77 SKB_GSO_GRE_CSUM | 78 SKB_GSO_IPIP | 79 SKB_GSO_SIT | 80 SKB_GSO_UDP_TUNNEL | 81 SKB_GSO_UDP_TUNNEL_CSUM | 82 SKB_GSO_TUNNEL_REMCSUM | 83 SKB_GSO_TCPV6 | 84 0))) 85 goto out; 86 87 skb_reset_network_header(skb); 88 nhoff = skb_network_header(skb) - skb_mac_header(skb); 89 if (unlikely(!pskb_may_pull(skb, sizeof(*ipv6h)))) 90 goto out; 91 92 encap = SKB_GSO_CB(skb)->encap_level > 0; 93 if (encap) 94 features &= skb->dev->hw_enc_features; 95 SKB_GSO_CB(skb)->encap_level += sizeof(*ipv6h); 96 97 ipv6h = ipv6_hdr(skb); 98 __skb_pull(skb, sizeof(*ipv6h)); 99 segs = ERR_PTR(-EPROTONOSUPPORT); 100 101 proto = ipv6_gso_pull_exthdrs(skb, ipv6h->nexthdr); 102 103 if (skb->encapsulation && 104 skb_shinfo(skb)->gso_type & (SKB_GSO_SIT|SKB_GSO_IPIP)) 105 udpfrag = proto == IPPROTO_UDP && encap; 106 else 107 udpfrag = proto == IPPROTO_UDP && !skb->encapsulation; 108 109 ops = rcu_dereference(inet6_offloads[proto]); 110 if (likely(ops && ops->callbacks.gso_segment)) { 111 skb_reset_transport_header(skb); 112 segs = ops->callbacks.gso_segment(skb, features); 113 } 114 115 if (IS_ERR(segs)) 116 goto out; 117 118 for (skb = segs; skb; skb = skb->next) { 119 ipv6h = (struct ipv6hdr *)(skb_mac_header(skb) + nhoff); 120 ipv6h->payload_len = htons(skb->len - nhoff - sizeof(*ipv6h)); 121 skb->network_header = (u8 *)ipv6h - skb->head; 122 123 if (udpfrag) { 124 unfrag_ip6hlen = ip6_find_1stfragopt(skb, &prevhdr); 125 fptr = (struct frag_hdr *)((u8 *)ipv6h + unfrag_ip6hlen); 126 fptr->frag_off = htons(offset); 127 if (skb->next) 128 fptr->frag_off |= htons(IP6_MF); 129 offset += (ntohs(ipv6h->payload_len) - 130 sizeof(struct frag_hdr)); 131 } 132 if (encap) 133 skb_reset_inner_headers(skb); 134 } 135 136 out: 137 return segs; 138 } 139 140 /* Return the total length of all the extension hdrs, following the same 141 * logic in ipv6_gso_pull_exthdrs() when parsing ext-hdrs. 142 */ 143 static int ipv6_exthdrs_len(struct ipv6hdr *iph, 144 const struct net_offload **opps) 145 { 146 struct ipv6_opt_hdr *opth = (void *)iph; 147 int len = 0, proto, optlen = sizeof(*iph); 148 149 proto = iph->nexthdr; 150 for (;;) { 151 if (proto != NEXTHDR_HOP) { 152 *opps = rcu_dereference(inet6_offloads[proto]); 153 if (unlikely(!(*opps))) 154 break; 155 if (!((*opps)->flags & INET6_PROTO_GSO_EXTHDR)) 156 break; 157 } 158 opth = (void *)opth + optlen; 159 optlen = ipv6_optlen(opth); 160 len += optlen; 161 proto = opth->nexthdr; 162 } 163 return len; 164 } 165 166 static struct sk_buff **ipv6_gro_receive(struct sk_buff **head, 167 struct sk_buff *skb) 168 { 169 const struct net_offload *ops; 170 struct sk_buff **pp = NULL; 171 struct sk_buff *p; 172 struct ipv6hdr *iph; 173 unsigned int nlen; 174 unsigned int hlen; 175 unsigned int off; 176 u16 flush = 1; 177 int proto; 178 179 off = skb_gro_offset(skb); 180 hlen = off + sizeof(*iph); 181 iph = skb_gro_header_fast(skb, off); 182 if (skb_gro_header_hard(skb, hlen)) { 183 iph = skb_gro_header_slow(skb, hlen, off); 184 if (unlikely(!iph)) 185 goto out; 186 } 187 188 skb_set_network_header(skb, off); 189 skb_gro_pull(skb, sizeof(*iph)); 190 skb_set_transport_header(skb, skb_gro_offset(skb)); 191 192 flush += ntohs(iph->payload_len) != skb_gro_len(skb); 193 194 rcu_read_lock(); 195 proto = iph->nexthdr; 196 ops = rcu_dereference(inet6_offloads[proto]); 197 if (!ops || !ops->callbacks.gro_receive) { 198 __pskb_pull(skb, skb_gro_offset(skb)); 199 proto = ipv6_gso_pull_exthdrs(skb, proto); 200 skb_gro_pull(skb, -skb_transport_offset(skb)); 201 skb_reset_transport_header(skb); 202 __skb_push(skb, skb_gro_offset(skb)); 203 204 ops = rcu_dereference(inet6_offloads[proto]); 205 if (!ops || !ops->callbacks.gro_receive) 206 goto out_unlock; 207 208 iph = ipv6_hdr(skb); 209 } 210 211 NAPI_GRO_CB(skb)->proto = proto; 212 213 flush--; 214 nlen = skb_network_header_len(skb); 215 216 for (p = *head; p; p = p->next) { 217 const struct ipv6hdr *iph2; 218 __be32 first_word; /* <Version:4><Traffic_Class:8><Flow_Label:20> */ 219 220 if (!NAPI_GRO_CB(p)->same_flow) 221 continue; 222 223 iph2 = (struct ipv6hdr *)(p->data + off); 224 first_word = *(__be32 *)iph ^ *(__be32 *)iph2; 225 226 /* All fields must match except length and Traffic Class. 227 * XXX skbs on the gro_list have all been parsed and pulled 228 * already so we don't need to compare nlen 229 * (nlen != (sizeof(*iph2) + ipv6_exthdrs_len(iph2, &ops))) 230 * memcmp() alone below is suffcient, right? 231 */ 232 if ((first_word & htonl(0xF00FFFFF)) || 233 memcmp(&iph->nexthdr, &iph2->nexthdr, 234 nlen - offsetof(struct ipv6hdr, nexthdr))) { 235 NAPI_GRO_CB(p)->same_flow = 0; 236 continue; 237 } 238 /* flush if Traffic Class fields are different */ 239 NAPI_GRO_CB(p)->flush |= !!(first_word & htonl(0x0FF00000)); 240 NAPI_GRO_CB(p)->flush |= flush; 241 242 /* Clear flush_id, there's really no concept of ID in IPv6. */ 243 NAPI_GRO_CB(p)->flush_id = 0; 244 } 245 246 NAPI_GRO_CB(skb)->flush |= flush; 247 248 skb_gro_postpull_rcsum(skb, iph, nlen); 249 250 pp = ops->callbacks.gro_receive(head, skb); 251 252 out_unlock: 253 rcu_read_unlock(); 254 255 out: 256 NAPI_GRO_CB(skb)->flush |= flush; 257 258 return pp; 259 } 260 261 static int ipv6_gro_complete(struct sk_buff *skb, int nhoff) 262 { 263 const struct net_offload *ops; 264 struct ipv6hdr *iph = (struct ipv6hdr *)(skb->data + nhoff); 265 int err = -ENOSYS; 266 267 iph->payload_len = htons(skb->len - nhoff - sizeof(*iph)); 268 269 rcu_read_lock(); 270 271 nhoff += sizeof(*iph) + ipv6_exthdrs_len(iph, &ops); 272 if (WARN_ON(!ops || !ops->callbacks.gro_complete)) 273 goto out_unlock; 274 275 err = ops->callbacks.gro_complete(skb, nhoff); 276 277 out_unlock: 278 rcu_read_unlock(); 279 280 return err; 281 } 282 283 static struct packet_offload ipv6_packet_offload __read_mostly = { 284 .type = cpu_to_be16(ETH_P_IPV6), 285 .callbacks = { 286 .gso_segment = ipv6_gso_segment, 287 .gro_receive = ipv6_gro_receive, 288 .gro_complete = ipv6_gro_complete, 289 }, 290 }; 291 292 static const struct net_offload sit_offload = { 293 .callbacks = { 294 .gso_segment = ipv6_gso_segment, 295 }, 296 }; 297 298 static int __init ipv6_offload_init(void) 299 { 300 301 if (tcpv6_offload_init() < 0) 302 pr_crit("%s: Cannot add TCP protocol offload\n", __func__); 303 if (udp_offload_init() < 0) 304 pr_crit("%s: Cannot add UDP protocol offload\n", __func__); 305 if (ipv6_exthdrs_offload_init() < 0) 306 pr_crit("%s: Cannot add EXTHDRS protocol offload\n", __func__); 307 308 dev_add_offload(&ipv6_packet_offload); 309 310 inet_add_offload(&sit_offload, IPPROTO_IPV6); 311 312 return 0; 313 } 314 315 fs_initcall(ipv6_offload_init); 316