1 // SPDX-License-Identifier: GPL-2.0-or-later 2 /* 3 * IPV6 GSO/GRO offload support 4 * Linux INET6 implementation 5 * 6 * UDPv6 GSO support 7 */ 8 #include <linux/skbuff.h> 9 #include <linux/netdevice.h> 10 #include <linux/indirect_call_wrapper.h> 11 #include <net/protocol.h> 12 #include <net/ipv6.h> 13 #include <net/udp.h> 14 #include <net/ip6_checksum.h> 15 #include "ip6_offload.h" 16 #include <net/gro.h> 17 #include <net/gso.h> 18 19 static struct sk_buff *udp6_ufo_fragment(struct sk_buff *skb, 20 netdev_features_t features) 21 { 22 struct sk_buff *segs = ERR_PTR(-EINVAL); 23 unsigned int mss; 24 unsigned int unfrag_ip6hlen, unfrag_len; 25 struct frag_hdr *fptr; 26 u8 *packet_start, *prevhdr; 27 u8 nexthdr; 28 u8 frag_hdr_sz = sizeof(struct frag_hdr); 29 __wsum csum; 30 int tnl_hlen; 31 int err; 32 33 if (skb->encapsulation && skb_shinfo(skb)->gso_type & 34 (SKB_GSO_UDP_TUNNEL|SKB_GSO_UDP_TUNNEL_CSUM)) 35 segs = skb_udp_tunnel_segment(skb, features, true); 36 else { 37 const struct ipv6hdr *ipv6h; 38 struct udphdr *uh; 39 40 if (!(skb_shinfo(skb)->gso_type & (SKB_GSO_UDP | SKB_GSO_UDP_L4))) 41 goto out; 42 43 if (!pskb_may_pull(skb, sizeof(struct udphdr))) 44 goto out; 45 46 if (skb_shinfo(skb)->gso_type & SKB_GSO_UDP_L4 && 47 !skb_gso_ok(skb, features | NETIF_F_GSO_ROBUST)) 48 return __udp_gso_segment(skb, features, true); 49 50 mss = skb_shinfo(skb)->gso_size; 51 if (unlikely(skb->len <= mss)) 52 goto out; 53 54 /* Do software UFO. Complete and fill in the UDP checksum as HW cannot 55 * do checksum of UDP packets sent as multiple IP fragments. 56 */ 57 58 uh = udp_hdr(skb); 59 ipv6h = ipv6_hdr(skb); 60 61 uh->check = 0; 62 csum = skb_checksum(skb, 0, skb->len, 0); 63 uh->check = udp_v6_check(skb->len, &ipv6h->saddr, 64 &ipv6h->daddr, csum); 65 if (uh->check == 0) 66 uh->check = CSUM_MANGLED_0; 67 68 skb->ip_summed = CHECKSUM_UNNECESSARY; 69 70 /* If there is no outer header we can fake a checksum offload 71 * due to the fact that we have already done the checksum in 72 * software prior to segmenting the frame. 73 */ 74 if (!skb->encap_hdr_csum) 75 features |= NETIF_F_HW_CSUM; 76 77 /* Check if there is enough headroom to insert fragment header. */ 78 tnl_hlen = skb_tnl_header_len(skb); 79 if (skb->mac_header < (tnl_hlen + frag_hdr_sz)) { 80 if (gso_pskb_expand_head(skb, tnl_hlen + frag_hdr_sz)) 81 goto out; 82 } 83 84 /* Find the unfragmentable header and shift it left by frag_hdr_sz 85 * bytes to insert fragment header. 86 */ 87 err = ip6_find_1stfragopt(skb, &prevhdr); 88 if (err < 0) 89 return ERR_PTR(err); 90 unfrag_ip6hlen = err; 91 nexthdr = *prevhdr; 92 *prevhdr = NEXTHDR_FRAGMENT; 93 unfrag_len = (skb_network_header(skb) - skb_mac_header(skb)) + 94 unfrag_ip6hlen + tnl_hlen; 95 packet_start = (u8 *) skb->head + SKB_GSO_CB(skb)->mac_offset; 96 memmove(packet_start-frag_hdr_sz, packet_start, unfrag_len); 97 98 SKB_GSO_CB(skb)->mac_offset -= frag_hdr_sz; 99 skb->mac_header -= frag_hdr_sz; 100 skb->network_header -= frag_hdr_sz; 101 102 fptr = (struct frag_hdr *)(skb_network_header(skb) + unfrag_ip6hlen); 103 fptr->nexthdr = nexthdr; 104 fptr->reserved = 0; 105 fptr->identification = ipv6_proxy_select_ident(dev_net(skb->dev), skb); 106 107 /* Fragment the skb. ipv6 header and the remaining fields of the 108 * fragment header are updated in ipv6_gso_segment() 109 */ 110 segs = skb_segment(skb, features); 111 } 112 113 out: 114 return segs; 115 } 116 117 static struct sock *udp6_gro_lookup_skb(struct sk_buff *skb, __be16 sport, 118 __be16 dport) 119 { 120 const struct ipv6hdr *iph = skb_gro_network_header(skb); 121 struct net *net = dev_net(skb->dev); 122 123 return __udp6_lib_lookup(net, &iph->saddr, sport, 124 &iph->daddr, dport, inet6_iif(skb), 125 inet6_sdif(skb), net->ipv4.udp_table, NULL); 126 } 127 128 INDIRECT_CALLABLE_SCOPE 129 struct sk_buff *udp6_gro_receive(struct list_head *head, struct sk_buff *skb) 130 { 131 struct udphdr *uh = udp_gro_udphdr(skb); 132 struct sock *sk = NULL; 133 struct sk_buff *pp; 134 135 if (unlikely(!uh)) 136 goto flush; 137 138 /* Don't bother verifying checksum if we're going to flush anyway. */ 139 if (NAPI_GRO_CB(skb)->flush) 140 goto skip; 141 142 if (skb_gro_checksum_validate_zero_check(skb, IPPROTO_UDP, uh->check, 143 ip6_gro_compute_pseudo)) 144 goto flush; 145 else if (uh->check) 146 skb_gro_checksum_try_convert(skb, IPPROTO_UDP, 147 ip6_gro_compute_pseudo); 148 149 skip: 150 NAPI_GRO_CB(skb)->is_ipv6 = 1; 151 152 if (static_branch_unlikely(&udpv6_encap_needed_key)) 153 sk = udp6_gro_lookup_skb(skb, uh->source, uh->dest); 154 155 pp = udp_gro_receive(head, skb, uh, sk); 156 return pp; 157 158 flush: 159 NAPI_GRO_CB(skb)->flush = 1; 160 return NULL; 161 } 162 163 INDIRECT_CALLABLE_SCOPE int udp6_gro_complete(struct sk_buff *skb, int nhoff) 164 { 165 const struct ipv6hdr *ipv6h = ipv6_hdr(skb); 166 struct udphdr *uh = (struct udphdr *)(skb->data + nhoff); 167 168 /* do fraglist only if there is no outer UDP encap (or we already processed it) */ 169 if (NAPI_GRO_CB(skb)->is_flist && !NAPI_GRO_CB(skb)->encap_mark) { 170 uh->len = htons(skb->len - nhoff); 171 172 skb_shinfo(skb)->gso_type |= (SKB_GSO_FRAGLIST|SKB_GSO_UDP_L4); 173 skb_shinfo(skb)->gso_segs = NAPI_GRO_CB(skb)->count; 174 175 if (skb->ip_summed == CHECKSUM_UNNECESSARY) { 176 if (skb->csum_level < SKB_MAX_CSUM_LEVEL) 177 skb->csum_level++; 178 } else { 179 skb->ip_summed = CHECKSUM_UNNECESSARY; 180 skb->csum_level = 0; 181 } 182 183 return 0; 184 } 185 186 if (uh->check) 187 uh->check = ~udp_v6_check(skb->len - nhoff, &ipv6h->saddr, 188 &ipv6h->daddr, 0); 189 190 return udp_gro_complete(skb, nhoff, udp6_lib_lookup_skb); 191 } 192 193 static const struct net_offload udpv6_offload = { 194 .callbacks = { 195 .gso_segment = udp6_ufo_fragment, 196 .gro_receive = udp6_gro_receive, 197 .gro_complete = udp6_gro_complete, 198 }, 199 }; 200 201 int udpv6_offload_init(void) 202 { 203 return inet6_add_offload(&udpv6_offload, IPPROTO_UDP); 204 } 205 206 int udpv6_offload_exit(void) 207 { 208 return inet6_del_offload(&udpv6_offload, IPPROTO_UDP); 209 } 210