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 return __udp_gso_segment(skb, features, true); 48 49 mss = skb_shinfo(skb)->gso_size; 50 if (unlikely(skb->len <= mss)) 51 goto out; 52 53 /* Do software UFO. Complete and fill in the UDP checksum as HW cannot 54 * do checksum of UDP packets sent as multiple IP fragments. 55 */ 56 57 uh = udp_hdr(skb); 58 ipv6h = ipv6_hdr(skb); 59 60 uh->check = 0; 61 csum = skb_checksum(skb, 0, skb->len, 0); 62 uh->check = udp_v6_check(skb->len, &ipv6h->saddr, 63 &ipv6h->daddr, csum); 64 if (uh->check == 0) 65 uh->check = CSUM_MANGLED_0; 66 67 skb->ip_summed = CHECKSUM_UNNECESSARY; 68 69 /* If there is no outer header we can fake a checksum offload 70 * due to the fact that we have already done the checksum in 71 * software prior to segmenting the frame. 72 */ 73 if (!skb->encap_hdr_csum) 74 features |= NETIF_F_HW_CSUM; 75 76 /* Check if there is enough headroom to insert fragment header. */ 77 tnl_hlen = skb_tnl_header_len(skb); 78 if (skb->mac_header < (tnl_hlen + frag_hdr_sz)) { 79 if (gso_pskb_expand_head(skb, tnl_hlen + frag_hdr_sz)) 80 goto out; 81 } 82 83 /* Find the unfragmentable header and shift it left by frag_hdr_sz 84 * bytes to insert fragment header. 85 */ 86 err = ip6_find_1stfragopt(skb, &prevhdr); 87 if (err < 0) 88 return ERR_PTR(err); 89 unfrag_ip6hlen = err; 90 nexthdr = *prevhdr; 91 *prevhdr = NEXTHDR_FRAGMENT; 92 unfrag_len = (skb_network_header(skb) - skb_mac_header(skb)) + 93 unfrag_ip6hlen + tnl_hlen; 94 packet_start = (u8 *) skb->head + SKB_GSO_CB(skb)->mac_offset; 95 memmove(packet_start-frag_hdr_sz, packet_start, unfrag_len); 96 97 SKB_GSO_CB(skb)->mac_offset -= frag_hdr_sz; 98 skb->mac_header -= frag_hdr_sz; 99 skb->network_header -= frag_hdr_sz; 100 101 fptr = (struct frag_hdr *)(skb_network_header(skb) + unfrag_ip6hlen); 102 fptr->nexthdr = nexthdr; 103 fptr->reserved = 0; 104 fptr->identification = ipv6_proxy_select_ident(dev_net(skb->dev), skb); 105 106 /* Fragment the skb. ipv6 header and the remaining fields of the 107 * fragment header are updated in ipv6_gso_segment() 108 */ 109 segs = skb_segment(skb, features); 110 } 111 112 out: 113 return segs; 114 } 115 116 static struct sock *udp6_gro_lookup_skb(struct sk_buff *skb, __be16 sport, 117 __be16 dport) 118 { 119 const struct ipv6hdr *iph = skb_gro_network_header(skb); 120 struct net *net = dev_net_rcu(skb->dev); 121 struct sock *sk; 122 int iif, sdif; 123 124 sk = udp_tunnel_sk(net, true); 125 if (sk && dport == htons(sk->sk_num)) 126 return sk; 127 128 inet6_get_iif_sdif(skb, &iif, &sdif); 129 130 return __udp6_lib_lookup(net, &iph->saddr, sport, 131 &iph->daddr, dport, iif, 132 sdif, net->ipv4.udp_table, NULL); 133 } 134 135 INDIRECT_CALLABLE_SCOPE 136 struct sk_buff *udp6_gro_receive(struct list_head *head, struct sk_buff *skb) 137 { 138 struct udphdr *uh = udp_gro_udphdr(skb); 139 struct sock *sk = NULL; 140 struct sk_buff *pp; 141 142 if (unlikely(!uh)) 143 goto flush; 144 145 /* Don't bother verifying checksum if we're going to flush anyway. */ 146 if (NAPI_GRO_CB(skb)->flush) 147 goto skip; 148 149 if (skb_gro_checksum_validate_zero_check(skb, IPPROTO_UDP, uh->check, 150 ip6_gro_compute_pseudo)) 151 goto flush; 152 else if (uh->check) 153 skb_gro_checksum_try_convert(skb, IPPROTO_UDP, 154 ip6_gro_compute_pseudo); 155 156 skip: 157 NAPI_GRO_CB(skb)->is_ipv6 = 1; 158 159 if (static_branch_unlikely(&udpv6_encap_needed_key)) 160 sk = udp6_gro_lookup_skb(skb, uh->source, uh->dest); 161 162 pp = udp_gro_receive(head, skb, uh, sk); 163 return pp; 164 165 flush: 166 NAPI_GRO_CB(skb)->flush = 1; 167 return NULL; 168 } 169 170 INDIRECT_CALLABLE_SCOPE int udp6_gro_complete(struct sk_buff *skb, int nhoff) 171 { 172 const u16 offset = NAPI_GRO_CB(skb)->network_offsets[skb->encapsulation]; 173 const struct ipv6hdr *ipv6h = (struct ipv6hdr *)(skb->data + offset); 174 struct udphdr *uh = (struct udphdr *)(skb->data + nhoff); 175 176 /* do fraglist only if there is no outer UDP encap (or we already processed it) */ 177 if (NAPI_GRO_CB(skb)->is_flist && !NAPI_GRO_CB(skb)->encap_mark) { 178 uh->len = htons(skb->len - nhoff); 179 180 skb_shinfo(skb)->gso_type |= (SKB_GSO_FRAGLIST|SKB_GSO_UDP_L4); 181 skb_shinfo(skb)->gso_segs = NAPI_GRO_CB(skb)->count; 182 183 __skb_incr_checksum_unnecessary(skb); 184 185 return 0; 186 } 187 188 if (uh->check) 189 uh->check = ~udp_v6_check(skb->len - nhoff, &ipv6h->saddr, 190 &ipv6h->daddr, 0); 191 192 return udp_gro_complete(skb, nhoff, udp6_lib_lookup_skb); 193 } 194 195 int __init udpv6_offload_init(void) 196 { 197 net_hotdata.udpv6_offload = (struct net_offload) { 198 .callbacks = { 199 .gso_segment = udp6_ufo_fragment, 200 .gro_receive = udp6_gro_receive, 201 .gro_complete = udp6_gro_complete, 202 }, 203 }; 204 return inet6_add_offload(&net_hotdata.udpv6_offload, IPPROTO_UDP); 205 } 206 207 int udpv6_offload_exit(void) 208 { 209 return inet6_del_offload(&net_hotdata.udpv6_offload, IPPROTO_UDP); 210 } 211