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