1 // SPDX-License-Identifier: GPL-2.0-only 2 /* 3 * IPv6 library code, needed by static components when full IPv6 support is 4 * not configured or static. These functions are needed by GSO/GRO implementation. 5 */ 6 #include <linux/export.h> 7 #include <net/ip.h> 8 #include <net/ipv6.h> 9 #include <net/ip6_fib.h> 10 #include <net/addrconf.h> 11 #include <net/secure_seq.h> 12 #include <linux/netfilter.h> 13 14 static u32 __ipv6_select_ident(struct net *net, 15 const struct in6_addr *dst, 16 const struct in6_addr *src) 17 { 18 return get_random_u32_above(0); 19 } 20 21 /* This function exists only for tap drivers that must support broken 22 * clients requesting UFO without specifying an IPv6 fragment ID. 23 * 24 * This is similar to ipv6_select_ident() but we use an independent hash 25 * seed to limit information leakage. 26 * 27 * The network header must be set before calling this. 28 */ 29 __be32 ipv6_proxy_select_ident(struct net *net, struct sk_buff *skb) 30 { 31 struct in6_addr buf[2]; 32 struct in6_addr *addrs; 33 u32 id; 34 35 addrs = skb_header_pointer(skb, 36 skb_network_offset(skb) + 37 offsetof(struct ipv6hdr, saddr), 38 sizeof(buf), buf); 39 if (!addrs) 40 return 0; 41 42 id = __ipv6_select_ident(net, &addrs[1], &addrs[0]); 43 return htonl(id); 44 } 45 46 __be32 ipv6_select_ident(struct net *net, 47 const struct in6_addr *daddr, 48 const struct in6_addr *saddr) 49 { 50 u32 id; 51 52 id = __ipv6_select_ident(net, daddr, saddr); 53 return htonl(id); 54 } 55 EXPORT_SYMBOL(ipv6_select_ident); 56 57 int ip6_find_1stfragopt(struct sk_buff *skb, u8 **nexthdr) 58 { 59 unsigned int offset = sizeof(struct ipv6hdr); 60 unsigned int packet_len = skb_tail_pointer(skb) - 61 skb_network_header(skb); 62 int found_rhdr = 0; 63 *nexthdr = &ipv6_hdr(skb)->nexthdr; 64 65 while (offset <= packet_len) { 66 struct ipv6_opt_hdr *exthdr; 67 68 switch (**nexthdr) { 69 70 case NEXTHDR_HOP: 71 break; 72 case NEXTHDR_ROUTING: 73 found_rhdr = 1; 74 break; 75 case NEXTHDR_DEST: 76 #if IS_ENABLED(CONFIG_IPV6_MIP6) 77 if (ipv6_find_tlv(skb, offset, IPV6_TLV_HAO) >= 0) 78 break; 79 #endif 80 if (found_rhdr) 81 return offset; 82 break; 83 default: 84 return offset; 85 } 86 87 if (offset + sizeof(struct ipv6_opt_hdr) > packet_len) 88 return -EINVAL; 89 90 exthdr = (struct ipv6_opt_hdr *)(skb_network_header(skb) + 91 offset); 92 offset += ipv6_optlen(exthdr); 93 if (offset > IPV6_MAXPLEN) 94 return -EINVAL; 95 *nexthdr = &exthdr->nexthdr; 96 } 97 98 return -EINVAL; 99 } 100 EXPORT_SYMBOL(ip6_find_1stfragopt); 101 102 int __ip6_local_out(struct net *net, struct sock *sk, struct sk_buff *skb) 103 { 104 ipv6_set_payload_len(ipv6_hdr(skb), skb->len - sizeof(struct ipv6hdr)); 105 IP6CB(skb)->nhoff = offsetof(struct ipv6hdr, nexthdr); 106 107 /* if egress device is enslaved to an L3 master device pass the 108 * skb to its handler for processing 109 */ 110 skb = l3mdev_ip6_out(sk, skb); 111 if (unlikely(!skb)) 112 return 0; 113 114 skb->protocol = htons(ETH_P_IPV6); 115 116 return nf_hook(NFPROTO_IPV6, NF_INET_LOCAL_OUT, 117 net, sk, skb, NULL, skb_dst_dev(skb), 118 dst_output); 119 } 120 EXPORT_SYMBOL_GPL(__ip6_local_out); 121 122 int ip6_local_out(struct net *net, struct sock *sk, struct sk_buff *skb) 123 { 124 int err; 125 126 err = __ip6_local_out(net, sk, skb); 127 if (likely(err == 1)) 128 err = dst_output(net, sk, skb); 129 130 return err; 131 } 132 EXPORT_SYMBOL_GPL(ip6_local_out); 133