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 rcu_read_lock(); 70 ops = rcu_dereference(inet6_offloads[ 71 ipv6_gso_pull_exthdrs(skb, ipv6h->nexthdr)]); 72 73 if (likely(ops && ops->callbacks.gso_send_check)) { 74 skb_reset_transport_header(skb); 75 err = ops->callbacks.gso_send_check(skb); 76 } 77 rcu_read_unlock(); 78 79 out: 80 return err; 81 } 82 83 static struct sk_buff *ipv6_gso_segment(struct sk_buff *skb, 84 netdev_features_t features) 85 { 86 struct sk_buff *segs = ERR_PTR(-EINVAL); 87 struct ipv6hdr *ipv6h; 88 const struct net_offload *ops; 89 int proto; 90 struct frag_hdr *fptr; 91 unsigned int unfrag_ip6hlen; 92 u8 *prevhdr; 93 int offset = 0; 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_UDP_TUNNEL | 101 SKB_GSO_MPLS | 102 SKB_GSO_TCPV6 | 103 0))) 104 goto out; 105 106 if (unlikely(!pskb_may_pull(skb, sizeof(*ipv6h)))) 107 goto out; 108 109 ipv6h = ipv6_hdr(skb); 110 __skb_pull(skb, sizeof(*ipv6h)); 111 segs = ERR_PTR(-EPROTONOSUPPORT); 112 113 proto = ipv6_gso_pull_exthdrs(skb, ipv6h->nexthdr); 114 rcu_read_lock(); 115 ops = rcu_dereference(inet6_offloads[proto]); 116 if (likely(ops && ops->callbacks.gso_segment)) { 117 skb_reset_transport_header(skb); 118 segs = ops->callbacks.gso_segment(skb, features); 119 } 120 rcu_read_unlock(); 121 122 if (IS_ERR(segs)) 123 goto out; 124 125 for (skb = segs; skb; skb = skb->next) { 126 ipv6h = ipv6_hdr(skb); 127 ipv6h->payload_len = htons(skb->len - skb->mac_len - 128 sizeof(*ipv6h)); 129 if (proto == IPPROTO_UDP) { 130 unfrag_ip6hlen = ip6_find_1stfragopt(skb, &prevhdr); 131 fptr = (struct frag_hdr *)(skb_network_header(skb) + 132 unfrag_ip6hlen); 133 fptr->frag_off = htons(offset); 134 if (skb->next != NULL) 135 fptr->frag_off |= htons(IP6_MF); 136 offset += (ntohs(ipv6h->payload_len) - 137 sizeof(struct frag_hdr)); 138 } 139 } 140 141 out: 142 return segs; 143 } 144 145 static struct sk_buff **ipv6_gro_receive(struct sk_buff **head, 146 struct sk_buff *skb) 147 { 148 const struct net_offload *ops; 149 struct sk_buff **pp = NULL; 150 struct sk_buff *p; 151 struct ipv6hdr *iph; 152 unsigned int nlen; 153 unsigned int hlen; 154 unsigned int off; 155 int flush = 1; 156 int proto; 157 __wsum csum; 158 159 off = skb_gro_offset(skb); 160 hlen = off + sizeof(*iph); 161 iph = skb_gro_header_fast(skb, off); 162 if (skb_gro_header_hard(skb, hlen)) { 163 iph = skb_gro_header_slow(skb, hlen, off); 164 if (unlikely(!iph)) 165 goto out; 166 } 167 168 skb_gro_pull(skb, sizeof(*iph)); 169 skb_set_transport_header(skb, skb_gro_offset(skb)); 170 171 flush += ntohs(iph->payload_len) != skb_gro_len(skb); 172 173 rcu_read_lock(); 174 proto = iph->nexthdr; 175 ops = rcu_dereference(inet6_offloads[proto]); 176 if (!ops || !ops->callbacks.gro_receive) { 177 __pskb_pull(skb, skb_gro_offset(skb)); 178 proto = ipv6_gso_pull_exthdrs(skb, proto); 179 skb_gro_pull(skb, -skb_transport_offset(skb)); 180 skb_reset_transport_header(skb); 181 __skb_push(skb, skb_gro_offset(skb)); 182 183 ops = rcu_dereference(inet6_offloads[proto]); 184 if (!ops || !ops->callbacks.gro_receive) 185 goto out_unlock; 186 187 iph = ipv6_hdr(skb); 188 } 189 190 NAPI_GRO_CB(skb)->proto = proto; 191 192 flush--; 193 nlen = skb_network_header_len(skb); 194 195 for (p = *head; p; p = p->next) { 196 const struct ipv6hdr *iph2; 197 __be32 first_word; /* <Version:4><Traffic_Class:8><Flow_Label:20> */ 198 199 if (!NAPI_GRO_CB(p)->same_flow) 200 continue; 201 202 iph2 = ipv6_hdr(p); 203 first_word = *(__be32 *)iph ^ *(__be32 *)iph2 ; 204 205 /* All fields must match except length and Traffic Class. */ 206 if (nlen != skb_network_header_len(p) || 207 (first_word & htonl(0xF00FFFFF)) || 208 memcmp(&iph->nexthdr, &iph2->nexthdr, 209 nlen - offsetof(struct ipv6hdr, nexthdr))) { 210 NAPI_GRO_CB(p)->same_flow = 0; 211 continue; 212 } 213 /* flush if Traffic Class fields are different */ 214 NAPI_GRO_CB(p)->flush |= !!(first_word & htonl(0x0FF00000)); 215 NAPI_GRO_CB(p)->flush |= flush; 216 } 217 218 NAPI_GRO_CB(skb)->flush |= flush; 219 220 csum = skb->csum; 221 skb_postpull_rcsum(skb, iph, skb_network_header_len(skb)); 222 223 pp = ops->callbacks.gro_receive(head, skb); 224 225 skb->csum = csum; 226 227 out_unlock: 228 rcu_read_unlock(); 229 230 out: 231 NAPI_GRO_CB(skb)->flush |= flush; 232 233 return pp; 234 } 235 236 static int ipv6_gro_complete(struct sk_buff *skb) 237 { 238 const struct net_offload *ops; 239 struct ipv6hdr *iph = ipv6_hdr(skb); 240 int err = -ENOSYS; 241 242 iph->payload_len = htons(skb->len - skb_network_offset(skb) - 243 sizeof(*iph)); 244 245 rcu_read_lock(); 246 ops = rcu_dereference(inet6_offloads[NAPI_GRO_CB(skb)->proto]); 247 if (WARN_ON(!ops || !ops->callbacks.gro_complete)) 248 goto out_unlock; 249 250 err = ops->callbacks.gro_complete(skb); 251 252 out_unlock: 253 rcu_read_unlock(); 254 255 return err; 256 } 257 258 static struct packet_offload ipv6_packet_offload __read_mostly = { 259 .type = cpu_to_be16(ETH_P_IPV6), 260 .callbacks = { 261 .gso_send_check = ipv6_gso_send_check, 262 .gso_segment = ipv6_gso_segment, 263 .gro_receive = ipv6_gro_receive, 264 .gro_complete = ipv6_gro_complete, 265 }, 266 }; 267 268 static int __init ipv6_offload_init(void) 269 { 270 271 if (tcpv6_offload_init() < 0) 272 pr_crit("%s: Cannot add TCP protocol offload\n", __func__); 273 if (udp_offload_init() < 0) 274 pr_crit("%s: Cannot add UDP protocol offload\n", __func__); 275 if (ipv6_exthdrs_offload_init() < 0) 276 pr_crit("%s: Cannot add EXTHDRS protocol offload\n", __func__); 277 278 dev_add_offload(&ipv6_packet_offload); 279 return 0; 280 } 281 282 fs_initcall(ipv6_offload_init); 283