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