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 unsigned int payload_len; 67 u8 *prevhdr; 68 int offset = 0; 69 bool encap, udpfrag; 70 int nhoff; 71 72 if (unlikely(skb_shinfo(skb)->gso_type & 73 ~(SKB_GSO_TCPV4 | 74 SKB_GSO_UDP | 75 SKB_GSO_DODGY | 76 SKB_GSO_TCP_ECN | 77 SKB_GSO_TCP_FIXEDID | 78 SKB_GSO_TCPV6 | 79 SKB_GSO_GRE | 80 SKB_GSO_GRE_CSUM | 81 SKB_GSO_IPIP | 82 SKB_GSO_SIT | 83 SKB_GSO_UDP_TUNNEL | 84 SKB_GSO_UDP_TUNNEL_CSUM | 85 SKB_GSO_TUNNEL_REMCSUM | 86 SKB_GSO_PARTIAL | 87 0))) 88 goto out; 89 90 skb_reset_network_header(skb); 91 nhoff = skb_network_header(skb) - skb_mac_header(skb); 92 if (unlikely(!pskb_may_pull(skb, sizeof(*ipv6h)))) 93 goto out; 94 95 encap = SKB_GSO_CB(skb)->encap_level > 0; 96 if (encap) 97 features &= skb->dev->hw_enc_features; 98 SKB_GSO_CB(skb)->encap_level += sizeof(*ipv6h); 99 100 ipv6h = ipv6_hdr(skb); 101 __skb_pull(skb, sizeof(*ipv6h)); 102 segs = ERR_PTR(-EPROTONOSUPPORT); 103 104 proto = ipv6_gso_pull_exthdrs(skb, ipv6h->nexthdr); 105 106 if (skb->encapsulation && 107 skb_shinfo(skb)->gso_type & (SKB_GSO_SIT|SKB_GSO_IPIP)) 108 udpfrag = proto == IPPROTO_UDP && encap; 109 else 110 udpfrag = proto == IPPROTO_UDP && !skb->encapsulation; 111 112 ops = rcu_dereference(inet6_offloads[proto]); 113 if (likely(ops && ops->callbacks.gso_segment)) { 114 skb_reset_transport_header(skb); 115 segs = ops->callbacks.gso_segment(skb, features); 116 } 117 118 if (IS_ERR(segs)) 119 goto out; 120 121 for (skb = segs; skb; skb = skb->next) { 122 ipv6h = (struct ipv6hdr *)(skb_mac_header(skb) + nhoff); 123 if (skb_is_gso(skb)) 124 payload_len = skb_shinfo(skb)->gso_size + 125 SKB_GSO_CB(skb)->data_offset + 126 skb->head - (unsigned char *)(ipv6h + 1); 127 else 128 payload_len = skb->len - nhoff - sizeof(*ipv6h); 129 ipv6h->payload_len = htons(payload_len); 130 skb->network_header = (u8 *)ipv6h - skb->head; 131 132 if (udpfrag) { 133 unfrag_ip6hlen = ip6_find_1stfragopt(skb, &prevhdr); 134 fptr = (struct frag_hdr *)((u8 *)ipv6h + unfrag_ip6hlen); 135 fptr->frag_off = htons(offset); 136 if (skb->next) 137 fptr->frag_off |= htons(IP6_MF); 138 offset += (ntohs(ipv6h->payload_len) - 139 sizeof(struct frag_hdr)); 140 } 141 if (encap) 142 skb_reset_inner_headers(skb); 143 } 144 145 out: 146 return segs; 147 } 148 149 /* Return the total length of all the extension hdrs, following the same 150 * logic in ipv6_gso_pull_exthdrs() when parsing ext-hdrs. 151 */ 152 static int ipv6_exthdrs_len(struct ipv6hdr *iph, 153 const struct net_offload **opps) 154 { 155 struct ipv6_opt_hdr *opth = (void *)iph; 156 int len = 0, proto, optlen = sizeof(*iph); 157 158 proto = iph->nexthdr; 159 for (;;) { 160 if (proto != NEXTHDR_HOP) { 161 *opps = rcu_dereference(inet6_offloads[proto]); 162 if (unlikely(!(*opps))) 163 break; 164 if (!((*opps)->flags & INET6_PROTO_GSO_EXTHDR)) 165 break; 166 } 167 opth = (void *)opth + optlen; 168 optlen = ipv6_optlen(opth); 169 len += optlen; 170 proto = opth->nexthdr; 171 } 172 return len; 173 } 174 175 static struct sk_buff **ipv6_gro_receive(struct sk_buff **head, 176 struct sk_buff *skb) 177 { 178 const struct net_offload *ops; 179 struct sk_buff **pp = NULL; 180 struct sk_buff *p; 181 struct ipv6hdr *iph; 182 unsigned int nlen; 183 unsigned int hlen; 184 unsigned int off; 185 u16 flush = 1; 186 int proto; 187 188 off = skb_gro_offset(skb); 189 hlen = off + sizeof(*iph); 190 iph = skb_gro_header_fast(skb, off); 191 if (skb_gro_header_hard(skb, hlen)) { 192 iph = skb_gro_header_slow(skb, hlen, off); 193 if (unlikely(!iph)) 194 goto out; 195 } 196 197 skb_set_network_header(skb, off); 198 skb_gro_pull(skb, sizeof(*iph)); 199 skb_set_transport_header(skb, skb_gro_offset(skb)); 200 201 flush += ntohs(iph->payload_len) != skb_gro_len(skb); 202 203 rcu_read_lock(); 204 proto = iph->nexthdr; 205 ops = rcu_dereference(inet6_offloads[proto]); 206 if (!ops || !ops->callbacks.gro_receive) { 207 __pskb_pull(skb, skb_gro_offset(skb)); 208 proto = ipv6_gso_pull_exthdrs(skb, proto); 209 skb_gro_pull(skb, -skb_transport_offset(skb)); 210 skb_reset_transport_header(skb); 211 __skb_push(skb, skb_gro_offset(skb)); 212 213 ops = rcu_dereference(inet6_offloads[proto]); 214 if (!ops || !ops->callbacks.gro_receive) 215 goto out_unlock; 216 217 iph = ipv6_hdr(skb); 218 } 219 220 NAPI_GRO_CB(skb)->proto = proto; 221 222 flush--; 223 nlen = skb_network_header_len(skb); 224 225 for (p = *head; p; p = p->next) { 226 const struct ipv6hdr *iph2; 227 __be32 first_word; /* <Version:4><Traffic_Class:8><Flow_Label:20> */ 228 229 if (!NAPI_GRO_CB(p)->same_flow) 230 continue; 231 232 iph2 = (struct ipv6hdr *)(p->data + off); 233 first_word = *(__be32 *)iph ^ *(__be32 *)iph2; 234 235 /* All fields must match except length and Traffic Class. 236 * XXX skbs on the gro_list have all been parsed and pulled 237 * already so we don't need to compare nlen 238 * (nlen != (sizeof(*iph2) + ipv6_exthdrs_len(iph2, &ops))) 239 * memcmp() alone below is suffcient, right? 240 */ 241 if ((first_word & htonl(0xF00FFFFF)) || 242 memcmp(&iph->nexthdr, &iph2->nexthdr, 243 nlen - offsetof(struct ipv6hdr, nexthdr))) { 244 NAPI_GRO_CB(p)->same_flow = 0; 245 continue; 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 = ops->callbacks.gro_receive(head, skb); 264 265 out_unlock: 266 rcu_read_unlock(); 267 268 out: 269 NAPI_GRO_CB(skb)->flush |= flush; 270 271 return pp; 272 } 273 274 static struct sk_buff **sit_gro_receive(struct sk_buff **head, 275 struct sk_buff *skb) 276 { 277 if (NAPI_GRO_CB(skb)->encap_mark) { 278 NAPI_GRO_CB(skb)->flush = 1; 279 return NULL; 280 } 281 282 NAPI_GRO_CB(skb)->encap_mark = 1; 283 284 return ipv6_gro_receive(head, skb); 285 } 286 287 static int ipv6_gro_complete(struct sk_buff *skb, int nhoff) 288 { 289 const struct net_offload *ops; 290 struct ipv6hdr *iph = (struct ipv6hdr *)(skb->data + nhoff); 291 int err = -ENOSYS; 292 293 if (skb->encapsulation) 294 skb_set_inner_network_header(skb, nhoff); 295 296 iph->payload_len = htons(skb->len - nhoff - sizeof(*iph)); 297 298 rcu_read_lock(); 299 300 nhoff += sizeof(*iph) + ipv6_exthdrs_len(iph, &ops); 301 if (WARN_ON(!ops || !ops->callbacks.gro_complete)) 302 goto out_unlock; 303 304 err = ops->callbacks.gro_complete(skb, nhoff); 305 306 out_unlock: 307 rcu_read_unlock(); 308 309 return err; 310 } 311 312 static int sit_gro_complete(struct sk_buff *skb, int nhoff) 313 { 314 skb->encapsulation = 1; 315 skb_shinfo(skb)->gso_type |= SKB_GSO_SIT; 316 return ipv6_gro_complete(skb, nhoff); 317 } 318 319 static struct packet_offload ipv6_packet_offload __read_mostly = { 320 .type = cpu_to_be16(ETH_P_IPV6), 321 .callbacks = { 322 .gso_segment = ipv6_gso_segment, 323 .gro_receive = ipv6_gro_receive, 324 .gro_complete = ipv6_gro_complete, 325 }, 326 }; 327 328 static const struct net_offload sit_offload = { 329 .callbacks = { 330 .gso_segment = ipv6_gso_segment, 331 .gro_receive = sit_gro_receive, 332 .gro_complete = sit_gro_complete, 333 }, 334 }; 335 336 static int __init ipv6_offload_init(void) 337 { 338 339 if (tcpv6_offload_init() < 0) 340 pr_crit("%s: Cannot add TCP protocol offload\n", __func__); 341 if (ipv6_exthdrs_offload_init() < 0) 342 pr_crit("%s: Cannot add EXTHDRS protocol offload\n", __func__); 343 344 dev_add_offload(&ipv6_packet_offload); 345 346 inet_add_offload(&sit_offload, IPPROTO_IPV6); 347 348 return 0; 349 } 350 351 fs_initcall(ipv6_offload_init); 352