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