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_TCPV6 | 102 0))) 103 goto out; 104 105 if (unlikely(!pskb_may_pull(skb, sizeof(*ipv6h)))) 106 goto out; 107 108 ipv6h = ipv6_hdr(skb); 109 __skb_pull(skb, sizeof(*ipv6h)); 110 segs = ERR_PTR(-EPROTONOSUPPORT); 111 112 proto = ipv6_gso_pull_exthdrs(skb, ipv6h->nexthdr); 113 rcu_read_lock(); 114 ops = rcu_dereference(inet6_offloads[proto]); 115 if (likely(ops && ops->callbacks.gso_segment)) { 116 skb_reset_transport_header(skb); 117 segs = ops->callbacks.gso_segment(skb, features); 118 } 119 rcu_read_unlock(); 120 121 if (IS_ERR(segs)) 122 goto out; 123 124 for (skb = segs; skb; skb = skb->next) { 125 ipv6h = ipv6_hdr(skb); 126 ipv6h->payload_len = htons(skb->len - skb->mac_len - 127 sizeof(*ipv6h)); 128 if (proto == IPPROTO_UDP) { 129 unfrag_ip6hlen = ip6_find_1stfragopt(skb, &prevhdr); 130 fptr = (struct frag_hdr *)(skb_network_header(skb) + 131 unfrag_ip6hlen); 132 fptr->frag_off = htons(offset); 133 if (skb->next != NULL) 134 fptr->frag_off |= htons(IP6_MF); 135 offset += (ntohs(ipv6h->payload_len) - 136 sizeof(struct frag_hdr)); 137 } 138 } 139 140 out: 141 return segs; 142 } 143 144 static struct sk_buff **ipv6_gro_receive(struct sk_buff **head, 145 struct sk_buff *skb) 146 { 147 const struct net_offload *ops; 148 struct sk_buff **pp = NULL; 149 struct sk_buff *p; 150 struct ipv6hdr *iph; 151 unsigned int nlen; 152 unsigned int hlen; 153 unsigned int off; 154 int flush = 1; 155 int proto; 156 __wsum csum; 157 158 off = skb_gro_offset(skb); 159 hlen = off + sizeof(*iph); 160 iph = skb_gro_header_fast(skb, off); 161 if (skb_gro_header_hard(skb, hlen)) { 162 iph = skb_gro_header_slow(skb, hlen, off); 163 if (unlikely(!iph)) 164 goto out; 165 } 166 167 skb_gro_pull(skb, sizeof(*iph)); 168 skb_set_transport_header(skb, skb_gro_offset(skb)); 169 170 flush += ntohs(iph->payload_len) != skb_gro_len(skb); 171 172 rcu_read_lock(); 173 proto = iph->nexthdr; 174 ops = rcu_dereference(inet6_offloads[proto]); 175 if (!ops || !ops->callbacks.gro_receive) { 176 __pskb_pull(skb, skb_gro_offset(skb)); 177 proto = ipv6_gso_pull_exthdrs(skb, proto); 178 skb_gro_pull(skb, -skb_transport_offset(skb)); 179 skb_reset_transport_header(skb); 180 __skb_push(skb, skb_gro_offset(skb)); 181 182 ops = rcu_dereference(inet6_offloads[proto]); 183 if (!ops || !ops->callbacks.gro_receive) 184 goto out_unlock; 185 186 iph = ipv6_hdr(skb); 187 } 188 189 NAPI_GRO_CB(skb)->proto = proto; 190 191 flush--; 192 nlen = skb_network_header_len(skb); 193 194 for (p = *head; p; p = p->next) { 195 const struct ipv6hdr *iph2; 196 __be32 first_word; /* <Version:4><Traffic_Class:8><Flow_Label:20> */ 197 198 if (!NAPI_GRO_CB(p)->same_flow) 199 continue; 200 201 iph2 = ipv6_hdr(p); 202 first_word = *(__be32 *)iph ^ *(__be32 *)iph2 ; 203 204 /* All fields must match except length and Traffic Class. */ 205 if (nlen != skb_network_header_len(p) || 206 (first_word & htonl(0xF00FFFFF)) || 207 memcmp(&iph->nexthdr, &iph2->nexthdr, 208 nlen - offsetof(struct ipv6hdr, nexthdr))) { 209 NAPI_GRO_CB(p)->same_flow = 0; 210 continue; 211 } 212 /* flush if Traffic Class fields are different */ 213 NAPI_GRO_CB(p)->flush |= !!(first_word & htonl(0x0FF00000)); 214 NAPI_GRO_CB(p)->flush |= flush; 215 } 216 217 NAPI_GRO_CB(skb)->flush |= flush; 218 219 csum = skb->csum; 220 skb_postpull_rcsum(skb, iph, skb_network_header_len(skb)); 221 222 pp = ops->callbacks.gro_receive(head, skb); 223 224 skb->csum = csum; 225 226 out_unlock: 227 rcu_read_unlock(); 228 229 out: 230 NAPI_GRO_CB(skb)->flush |= flush; 231 232 return pp; 233 } 234 235 static int ipv6_gro_complete(struct sk_buff *skb) 236 { 237 const struct net_offload *ops; 238 struct ipv6hdr *iph = ipv6_hdr(skb); 239 int err = -ENOSYS; 240 241 iph->payload_len = htons(skb->len - skb_network_offset(skb) - 242 sizeof(*iph)); 243 244 rcu_read_lock(); 245 ops = rcu_dereference(inet6_offloads[NAPI_GRO_CB(skb)->proto]); 246 if (WARN_ON(!ops || !ops->callbacks.gro_complete)) 247 goto out_unlock; 248 249 err = ops->callbacks.gro_complete(skb); 250 251 out_unlock: 252 rcu_read_unlock(); 253 254 return err; 255 } 256 257 static struct packet_offload ipv6_packet_offload __read_mostly = { 258 .type = cpu_to_be16(ETH_P_IPV6), 259 .callbacks = { 260 .gso_send_check = ipv6_gso_send_check, 261 .gso_segment = ipv6_gso_segment, 262 .gro_receive = ipv6_gro_receive, 263 .gro_complete = ipv6_gro_complete, 264 }, 265 }; 266 267 static int __init ipv6_offload_init(void) 268 { 269 270 if (tcpv6_offload_init() < 0) 271 pr_crit("%s: Cannot add TCP protocol offload\n", __func__); 272 if (udp_offload_init() < 0) 273 pr_crit("%s: Cannot add UDP protocol offload\n", __func__); 274 if (ipv6_exthdrs_offload_init() < 0) 275 pr_crit("%s: Cannot add EXTHDRS protocol offload\n", __func__); 276 277 dev_add_offload(&ipv6_packet_offload); 278 return 0; 279 } 280 281 fs_initcall(ipv6_offload_init); 282