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 #include <net/inet_common.h> 20 21 #include "ip6_offload.h" 22 23 static int ipv6_gso_pull_exthdrs(struct sk_buff *skb, int proto) 24 { 25 const struct net_offload *ops = NULL; 26 27 for (;;) { 28 struct ipv6_opt_hdr *opth; 29 int len; 30 31 if (proto != NEXTHDR_HOP) { 32 ops = rcu_dereference(inet6_offloads[proto]); 33 34 if (unlikely(!ops)) 35 break; 36 37 if (!(ops->flags & INET6_PROTO_GSO_EXTHDR)) 38 break; 39 } 40 41 if (unlikely(!pskb_may_pull(skb, 8))) 42 break; 43 44 opth = (void *)skb->data; 45 len = ipv6_optlen(opth); 46 47 if (unlikely(!pskb_may_pull(skb, len))) 48 break; 49 50 opth = (void *)skb->data; 51 proto = opth->nexthdr; 52 __skb_pull(skb, len); 53 } 54 55 return proto; 56 } 57 58 static struct sk_buff *ipv6_gso_segment(struct sk_buff *skb, 59 netdev_features_t features) 60 { 61 struct sk_buff *segs = ERR_PTR(-EINVAL); 62 struct ipv6hdr *ipv6h; 63 const struct net_offload *ops; 64 int proto; 65 struct frag_hdr *fptr; 66 unsigned int payload_len; 67 u8 *prevhdr; 68 int offset = 0; 69 bool encap, udpfrag; 70 int nhoff; 71 bool gso_partial; 72 73 skb_reset_network_header(skb); 74 nhoff = skb_network_header(skb) - skb_mac_header(skb); 75 if (unlikely(!pskb_may_pull(skb, sizeof(*ipv6h)))) 76 goto out; 77 78 encap = SKB_GSO_CB(skb)->encap_level > 0; 79 if (encap) 80 features &= skb->dev->hw_enc_features; 81 SKB_GSO_CB(skb)->encap_level += sizeof(*ipv6h); 82 83 ipv6h = ipv6_hdr(skb); 84 __skb_pull(skb, sizeof(*ipv6h)); 85 segs = ERR_PTR(-EPROTONOSUPPORT); 86 87 proto = ipv6_gso_pull_exthdrs(skb, ipv6h->nexthdr); 88 89 if (skb->encapsulation && 90 skb_shinfo(skb)->gso_type & (SKB_GSO_IPXIP4 | SKB_GSO_IPXIP6)) 91 udpfrag = proto == IPPROTO_UDP && encap && 92 (skb_shinfo(skb)->gso_type & SKB_GSO_UDP); 93 else 94 udpfrag = proto == IPPROTO_UDP && !skb->encapsulation && 95 (skb_shinfo(skb)->gso_type & SKB_GSO_UDP); 96 97 ops = rcu_dereference(inet6_offloads[proto]); 98 if (likely(ops && ops->callbacks.gso_segment)) { 99 skb_reset_transport_header(skb); 100 segs = ops->callbacks.gso_segment(skb, features); 101 } 102 103 if (IS_ERR_OR_NULL(segs)) 104 goto out; 105 106 gso_partial = !!(skb_shinfo(segs)->gso_type & SKB_GSO_PARTIAL); 107 108 for (skb = segs; skb; skb = skb->next) { 109 ipv6h = (struct ipv6hdr *)(skb_mac_header(skb) + nhoff); 110 if (gso_partial && skb_is_gso(skb)) 111 payload_len = skb_shinfo(skb)->gso_size + 112 SKB_GSO_CB(skb)->data_offset + 113 skb->head - (unsigned char *)(ipv6h + 1); 114 else 115 payload_len = skb->len - nhoff - sizeof(*ipv6h); 116 ipv6h->payload_len = htons(payload_len); 117 skb->network_header = (u8 *)ipv6h - skb->head; 118 skb_reset_mac_len(skb); 119 120 if (udpfrag) { 121 int err = ip6_find_1stfragopt(skb, &prevhdr); 122 if (err < 0) { 123 kfree_skb_list(segs); 124 return ERR_PTR(err); 125 } 126 fptr = (struct frag_hdr *)((u8 *)ipv6h + err); 127 fptr->frag_off = htons(offset); 128 if (skb->next) 129 fptr->frag_off |= htons(IP6_MF); 130 offset += (ntohs(ipv6h->payload_len) - 131 sizeof(struct frag_hdr)); 132 } 133 if (encap) 134 skb_reset_inner_headers(skb); 135 } 136 137 out: 138 return segs; 139 } 140 141 /* Return the total length of all the extension hdrs, following the same 142 * logic in ipv6_gso_pull_exthdrs() when parsing ext-hdrs. 143 */ 144 static int ipv6_exthdrs_len(struct ipv6hdr *iph, 145 const struct net_offload **opps) 146 { 147 struct ipv6_opt_hdr *opth = (void *)iph; 148 int len = 0, proto, optlen = sizeof(*iph); 149 150 proto = iph->nexthdr; 151 for (;;) { 152 if (proto != NEXTHDR_HOP) { 153 *opps = rcu_dereference(inet6_offloads[proto]); 154 if (unlikely(!(*opps))) 155 break; 156 if (!((*opps)->flags & INET6_PROTO_GSO_EXTHDR)) 157 break; 158 } 159 opth = (void *)opth + optlen; 160 optlen = ipv6_optlen(opth); 161 len += optlen; 162 proto = opth->nexthdr; 163 } 164 return len; 165 } 166 167 static struct sk_buff *ipv6_gro_receive(struct list_head *head, 168 struct sk_buff *skb) 169 { 170 const struct net_offload *ops; 171 struct sk_buff *pp = NULL; 172 struct sk_buff *p; 173 struct ipv6hdr *iph; 174 unsigned int nlen; 175 unsigned int hlen; 176 unsigned int off; 177 u16 flush = 1; 178 int proto; 179 180 off = skb_gro_offset(skb); 181 hlen = off + sizeof(*iph); 182 iph = skb_gro_header_fast(skb, off); 183 if (skb_gro_header_hard(skb, hlen)) { 184 iph = skb_gro_header_slow(skb, hlen, off); 185 if (unlikely(!iph)) 186 goto out; 187 } 188 189 skb_set_network_header(skb, off); 190 skb_gro_pull(skb, sizeof(*iph)); 191 skb_set_transport_header(skb, skb_gro_offset(skb)); 192 193 flush += ntohs(iph->payload_len) != skb_gro_len(skb); 194 195 rcu_read_lock(); 196 proto = iph->nexthdr; 197 ops = rcu_dereference(inet6_offloads[proto]); 198 if (!ops || !ops->callbacks.gro_receive) { 199 __pskb_pull(skb, skb_gro_offset(skb)); 200 skb_gro_frag0_invalidate(skb); 201 proto = ipv6_gso_pull_exthdrs(skb, proto); 202 skb_gro_pull(skb, -skb_transport_offset(skb)); 203 skb_reset_transport_header(skb); 204 __skb_push(skb, skb_gro_offset(skb)); 205 206 ops = rcu_dereference(inet6_offloads[proto]); 207 if (!ops || !ops->callbacks.gro_receive) 208 goto out_unlock; 209 210 iph = ipv6_hdr(skb); 211 } 212 213 NAPI_GRO_CB(skb)->proto = proto; 214 215 flush--; 216 nlen = skb_network_header_len(skb); 217 218 list_for_each_entry(p, head, list) { 219 const struct ipv6hdr *iph2; 220 __be32 first_word; /* <Version:4><Traffic_Class:8><Flow_Label:20> */ 221 222 if (!NAPI_GRO_CB(p)->same_flow) 223 continue; 224 225 iph2 = (struct ipv6hdr *)(p->data + off); 226 first_word = *(__be32 *)iph ^ *(__be32 *)iph2; 227 228 /* All fields must match except length and Traffic Class. 229 * XXX skbs on the gro_list have all been parsed and pulled 230 * already so we don't need to compare nlen 231 * (nlen != (sizeof(*iph2) + ipv6_exthdrs_len(iph2, &ops))) 232 * memcmp() alone below is sufficient, right? 233 */ 234 if ((first_word & htonl(0xF00FFFFF)) || 235 !ipv6_addr_equal(&iph->saddr, &iph2->saddr) || 236 !ipv6_addr_equal(&iph->daddr, &iph2->daddr) || 237 *(u16 *)&iph->nexthdr != *(u16 *)&iph2->nexthdr) { 238 not_same_flow: 239 NAPI_GRO_CB(p)->same_flow = 0; 240 continue; 241 } 242 if (unlikely(nlen > sizeof(struct ipv6hdr))) { 243 if (memcmp(iph + 1, iph2 + 1, 244 nlen - sizeof(struct ipv6hdr))) 245 goto not_same_flow; 246 } 247 /* flush if Traffic Class fields are different */ 248 NAPI_GRO_CB(p)->flush |= !!(first_word & htonl(0x0FF00000)); 249 NAPI_GRO_CB(p)->flush |= flush; 250 251 /* If the previous IP ID value was based on an atomic 252 * datagram we can overwrite the value and ignore it. 253 */ 254 if (NAPI_GRO_CB(skb)->is_atomic) 255 NAPI_GRO_CB(p)->flush_id = 0; 256 } 257 258 NAPI_GRO_CB(skb)->is_atomic = true; 259 NAPI_GRO_CB(skb)->flush |= flush; 260 261 skb_gro_postpull_rcsum(skb, iph, nlen); 262 263 pp = call_gro_receive(ops->callbacks.gro_receive, head, skb); 264 265 out_unlock: 266 rcu_read_unlock(); 267 268 out: 269 skb_gro_flush_final(skb, pp, flush); 270 271 return pp; 272 } 273 274 static struct sk_buff *sit_ip6ip6_gro_receive(struct list_head *head, 275 struct sk_buff *skb) 276 { 277 /* Common GRO receive for SIT and IP6IP6 */ 278 279 if (NAPI_GRO_CB(skb)->encap_mark) { 280 NAPI_GRO_CB(skb)->flush = 1; 281 return NULL; 282 } 283 284 NAPI_GRO_CB(skb)->encap_mark = 1; 285 286 return ipv6_gro_receive(head, skb); 287 } 288 289 static struct sk_buff *ip4ip6_gro_receive(struct list_head *head, 290 struct sk_buff *skb) 291 { 292 /* Common GRO receive for SIT and IP6IP6 */ 293 294 if (NAPI_GRO_CB(skb)->encap_mark) { 295 NAPI_GRO_CB(skb)->flush = 1; 296 return NULL; 297 } 298 299 NAPI_GRO_CB(skb)->encap_mark = 1; 300 301 return inet_gro_receive(head, skb); 302 } 303 304 static int ipv6_gro_complete(struct sk_buff *skb, int nhoff) 305 { 306 const struct net_offload *ops; 307 struct ipv6hdr *iph = (struct ipv6hdr *)(skb->data + nhoff); 308 int err = -ENOSYS; 309 310 if (skb->encapsulation) { 311 skb_set_inner_protocol(skb, cpu_to_be16(ETH_P_IPV6)); 312 skb_set_inner_network_header(skb, nhoff); 313 } 314 315 iph->payload_len = htons(skb->len - nhoff - sizeof(*iph)); 316 317 rcu_read_lock(); 318 319 nhoff += sizeof(*iph) + ipv6_exthdrs_len(iph, &ops); 320 if (WARN_ON(!ops || !ops->callbacks.gro_complete)) 321 goto out_unlock; 322 323 err = ops->callbacks.gro_complete(skb, nhoff); 324 325 out_unlock: 326 rcu_read_unlock(); 327 328 return err; 329 } 330 331 static int sit_gro_complete(struct sk_buff *skb, int nhoff) 332 { 333 skb->encapsulation = 1; 334 skb_shinfo(skb)->gso_type |= SKB_GSO_IPXIP4; 335 return ipv6_gro_complete(skb, nhoff); 336 } 337 338 static int ip6ip6_gro_complete(struct sk_buff *skb, int nhoff) 339 { 340 skb->encapsulation = 1; 341 skb_shinfo(skb)->gso_type |= SKB_GSO_IPXIP6; 342 return ipv6_gro_complete(skb, nhoff); 343 } 344 345 static int ip4ip6_gro_complete(struct sk_buff *skb, int nhoff) 346 { 347 skb->encapsulation = 1; 348 skb_shinfo(skb)->gso_type |= SKB_GSO_IPXIP6; 349 return inet_gro_complete(skb, nhoff); 350 } 351 352 static struct packet_offload ipv6_packet_offload __read_mostly = { 353 .type = cpu_to_be16(ETH_P_IPV6), 354 .callbacks = { 355 .gso_segment = ipv6_gso_segment, 356 .gro_receive = ipv6_gro_receive, 357 .gro_complete = ipv6_gro_complete, 358 }, 359 }; 360 361 static const struct net_offload sit_offload = { 362 .callbacks = { 363 .gso_segment = ipv6_gso_segment, 364 .gro_receive = sit_ip6ip6_gro_receive, 365 .gro_complete = sit_gro_complete, 366 }, 367 }; 368 369 static const struct net_offload ip4ip6_offload = { 370 .callbacks = { 371 .gso_segment = inet_gso_segment, 372 .gro_receive = ip4ip6_gro_receive, 373 .gro_complete = ip4ip6_gro_complete, 374 }, 375 }; 376 377 static const struct net_offload ip6ip6_offload = { 378 .callbacks = { 379 .gso_segment = ipv6_gso_segment, 380 .gro_receive = sit_ip6ip6_gro_receive, 381 .gro_complete = ip6ip6_gro_complete, 382 }, 383 }; 384 static int __init ipv6_offload_init(void) 385 { 386 387 if (tcpv6_offload_init() < 0) 388 pr_crit("%s: Cannot add TCP protocol offload\n", __func__); 389 if (ipv6_exthdrs_offload_init() < 0) 390 pr_crit("%s: Cannot add EXTHDRS protocol offload\n", __func__); 391 392 dev_add_offload(&ipv6_packet_offload); 393 394 inet_add_offload(&sit_offload, IPPROTO_IPV6); 395 inet6_add_offload(&ip6ip6_offload, IPPROTO_IPV6); 396 inet6_add_offload(&ip4ip6_offload, IPPROTO_IPIP); 397 398 return 0; 399 } 400 401 fs_initcall(ipv6_offload_init); 402