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 proto = opth->nexthdr; 50 __skb_pull(skb, len); 51 } 52 53 return proto; 54 } 55 56 static int ipv6_gso_send_check(struct sk_buff *skb) 57 { 58 const struct ipv6hdr *ipv6h; 59 const struct net_offload *ops; 60 int err = -EINVAL; 61 62 if (unlikely(!pskb_may_pull(skb, sizeof(*ipv6h)))) 63 goto out; 64 65 ipv6h = ipv6_hdr(skb); 66 __skb_pull(skb, sizeof(*ipv6h)); 67 err = -EPROTONOSUPPORT; 68 69 ops = rcu_dereference(inet6_offloads[ 70 ipv6_gso_pull_exthdrs(skb, ipv6h->nexthdr)]); 71 72 if (likely(ops && ops->callbacks.gso_send_check)) { 73 skb_reset_transport_header(skb); 74 err = ops->callbacks.gso_send_check(skb); 75 } 76 77 out: 78 return err; 79 } 80 81 static struct sk_buff *ipv6_gso_segment(struct sk_buff *skb, 82 netdev_features_t features) 83 { 84 struct sk_buff *segs = ERR_PTR(-EINVAL); 85 struct ipv6hdr *ipv6h; 86 const struct net_offload *ops; 87 int proto; 88 struct frag_hdr *fptr; 89 unsigned int unfrag_ip6hlen; 90 u8 *prevhdr; 91 int offset = 0; 92 bool encap, udpfrag; 93 int nhoff; 94 95 if (unlikely(skb_shinfo(skb)->gso_type & 96 ~(SKB_GSO_UDP | 97 SKB_GSO_DODGY | 98 SKB_GSO_TCP_ECN | 99 SKB_GSO_GRE | 100 SKB_GSO_GRE_CSUM | 101 SKB_GSO_IPIP | 102 SKB_GSO_SIT | 103 SKB_GSO_UDP_TUNNEL | 104 SKB_GSO_UDP_TUNNEL_CSUM | 105 SKB_GSO_MPLS | 106 SKB_GSO_TCPV6 | 107 0))) 108 goto out; 109 110 skb_reset_network_header(skb); 111 nhoff = skb_network_header(skb) - skb_mac_header(skb); 112 if (unlikely(!pskb_may_pull(skb, sizeof(*ipv6h)))) 113 goto out; 114 115 encap = SKB_GSO_CB(skb)->encap_level > 0; 116 if (encap) 117 features = skb->dev->hw_enc_features & netif_skb_features(skb); 118 SKB_GSO_CB(skb)->encap_level += sizeof(*ipv6h); 119 120 ipv6h = ipv6_hdr(skb); 121 __skb_pull(skb, sizeof(*ipv6h)); 122 segs = ERR_PTR(-EPROTONOSUPPORT); 123 124 proto = ipv6_gso_pull_exthdrs(skb, ipv6h->nexthdr); 125 126 if (skb->encapsulation && 127 skb_shinfo(skb)->gso_type & (SKB_GSO_SIT|SKB_GSO_IPIP)) 128 udpfrag = proto == IPPROTO_UDP && encap; 129 else 130 udpfrag = proto == IPPROTO_UDP && !skb->encapsulation; 131 132 ops = rcu_dereference(inet6_offloads[proto]); 133 if (likely(ops && ops->callbacks.gso_segment)) { 134 skb_reset_transport_header(skb); 135 segs = ops->callbacks.gso_segment(skb, features); 136 } 137 138 if (IS_ERR(segs)) 139 goto out; 140 141 for (skb = segs; skb; skb = skb->next) { 142 ipv6h = (struct ipv6hdr *)(skb_mac_header(skb) + nhoff); 143 ipv6h->payload_len = htons(skb->len - nhoff - sizeof(*ipv6h)); 144 skb->network_header = (u8 *)ipv6h - skb->head; 145 146 if (udpfrag) { 147 unfrag_ip6hlen = ip6_find_1stfragopt(skb, &prevhdr); 148 fptr = (struct frag_hdr *)((u8 *)ipv6h + unfrag_ip6hlen); 149 fptr->frag_off = htons(offset); 150 if (skb->next != NULL) 151 fptr->frag_off |= htons(IP6_MF); 152 offset += (ntohs(ipv6h->payload_len) - 153 sizeof(struct frag_hdr)); 154 } 155 if (encap) 156 skb_reset_inner_headers(skb); 157 } 158 159 out: 160 return segs; 161 } 162 163 /* Return the total length of all the extension hdrs, following the same 164 * logic in ipv6_gso_pull_exthdrs() when parsing ext-hdrs. 165 */ 166 static int ipv6_exthdrs_len(struct ipv6hdr *iph, 167 const struct net_offload **opps) 168 { 169 struct ipv6_opt_hdr *opth = (void *)iph; 170 int len = 0, proto, optlen = sizeof(*iph); 171 172 proto = iph->nexthdr; 173 for (;;) { 174 if (proto != NEXTHDR_HOP) { 175 *opps = rcu_dereference(inet6_offloads[proto]); 176 if (unlikely(!(*opps))) 177 break; 178 if (!((*opps)->flags & INET6_PROTO_GSO_EXTHDR)) 179 break; 180 } 181 opth = (void *)opth + optlen; 182 optlen = ipv6_optlen(opth); 183 len += optlen; 184 proto = opth->nexthdr; 185 } 186 return len; 187 } 188 189 static struct sk_buff **ipv6_gro_receive(struct sk_buff **head, 190 struct sk_buff *skb) 191 { 192 const struct net_offload *ops; 193 struct sk_buff **pp = NULL; 194 struct sk_buff *p; 195 struct ipv6hdr *iph; 196 unsigned int nlen; 197 unsigned int hlen; 198 unsigned int off; 199 u16 flush = 1; 200 int proto; 201 202 off = skb_gro_offset(skb); 203 hlen = off + sizeof(*iph); 204 iph = skb_gro_header_fast(skb, off); 205 if (skb_gro_header_hard(skb, hlen)) { 206 iph = skb_gro_header_slow(skb, hlen, off); 207 if (unlikely(!iph)) 208 goto out; 209 } 210 211 skb_set_network_header(skb, off); 212 skb_gro_pull(skb, sizeof(*iph)); 213 skb_set_transport_header(skb, skb_gro_offset(skb)); 214 215 flush += ntohs(iph->payload_len) != skb_gro_len(skb); 216 217 rcu_read_lock(); 218 proto = iph->nexthdr; 219 ops = rcu_dereference(inet6_offloads[proto]); 220 if (!ops || !ops->callbacks.gro_receive) { 221 __pskb_pull(skb, skb_gro_offset(skb)); 222 proto = ipv6_gso_pull_exthdrs(skb, proto); 223 skb_gro_pull(skb, -skb_transport_offset(skb)); 224 skb_reset_transport_header(skb); 225 __skb_push(skb, skb_gro_offset(skb)); 226 227 ops = rcu_dereference(inet6_offloads[proto]); 228 if (!ops || !ops->callbacks.gro_receive) 229 goto out_unlock; 230 231 iph = ipv6_hdr(skb); 232 } 233 234 NAPI_GRO_CB(skb)->proto = proto; 235 236 flush--; 237 nlen = skb_network_header_len(skb); 238 239 for (p = *head; p; p = p->next) { 240 const struct ipv6hdr *iph2; 241 __be32 first_word; /* <Version:4><Traffic_Class:8><Flow_Label:20> */ 242 243 if (!NAPI_GRO_CB(p)->same_flow) 244 continue; 245 246 iph2 = (struct ipv6hdr *)(p->data + off); 247 first_word = *(__be32 *)iph ^ *(__be32 *)iph2 ; 248 249 /* All fields must match except length and Traffic Class. 250 * XXX skbs on the gro_list have all been parsed and pulled 251 * already so we don't need to compare nlen 252 * (nlen != (sizeof(*iph2) + ipv6_exthdrs_len(iph2, &ops))) 253 * memcmp() alone below is suffcient, right? 254 */ 255 if ((first_word & htonl(0xF00FFFFF)) || 256 memcmp(&iph->nexthdr, &iph2->nexthdr, 257 nlen - offsetof(struct ipv6hdr, nexthdr))) { 258 NAPI_GRO_CB(p)->same_flow = 0; 259 continue; 260 } 261 /* flush if Traffic Class fields are different */ 262 NAPI_GRO_CB(p)->flush |= !!(first_word & htonl(0x0FF00000)); 263 NAPI_GRO_CB(p)->flush |= flush; 264 } 265 266 NAPI_GRO_CB(skb)->flush |= flush; 267 268 skb_gro_postpull_rcsum(skb, iph, nlen); 269 270 pp = ops->callbacks.gro_receive(head, skb); 271 272 out_unlock: 273 rcu_read_unlock(); 274 275 out: 276 NAPI_GRO_CB(skb)->flush |= flush; 277 278 return pp; 279 } 280 281 static int ipv6_gro_complete(struct sk_buff *skb, int nhoff) 282 { 283 const struct net_offload *ops; 284 struct ipv6hdr *iph = (struct ipv6hdr *)(skb->data + nhoff); 285 int err = -ENOSYS; 286 287 iph->payload_len = htons(skb->len - nhoff - sizeof(*iph)); 288 289 rcu_read_lock(); 290 291 nhoff += sizeof(*iph) + ipv6_exthdrs_len(iph, &ops); 292 if (WARN_ON(!ops || !ops->callbacks.gro_complete)) 293 goto out_unlock; 294 295 err = ops->callbacks.gro_complete(skb, nhoff); 296 297 out_unlock: 298 rcu_read_unlock(); 299 300 return err; 301 } 302 303 static struct packet_offload ipv6_packet_offload __read_mostly = { 304 .type = cpu_to_be16(ETH_P_IPV6), 305 .callbacks = { 306 .gso_send_check = ipv6_gso_send_check, 307 .gso_segment = ipv6_gso_segment, 308 .gro_receive = ipv6_gro_receive, 309 .gro_complete = ipv6_gro_complete, 310 }, 311 }; 312 313 static const struct net_offload sit_offload = { 314 .callbacks = { 315 .gso_send_check = ipv6_gso_send_check, 316 .gso_segment = ipv6_gso_segment, 317 }, 318 }; 319 320 static int __init ipv6_offload_init(void) 321 { 322 323 if (tcpv6_offload_init() < 0) 324 pr_crit("%s: Cannot add TCP protocol offload\n", __func__); 325 if (udp_offload_init() < 0) 326 pr_crit("%s: Cannot add UDP protocol offload\n", __func__); 327 if (ipv6_exthdrs_offload_init() < 0) 328 pr_crit("%s: Cannot add EXTHDRS protocol offload\n", __func__); 329 330 dev_add_offload(&ipv6_packet_offload); 331 332 inet_add_offload(&sit_offload, IPPROTO_IPV6); 333 334 return 0; 335 } 336 337 fs_initcall(ipv6_offload_init); 338