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 EXPORT_SYMBOL_GPL(ipv6_proxy_select_ident); 46 47 __be32 ipv6_select_ident(struct net *net, 48 const struct in6_addr *daddr, 49 const struct in6_addr *saddr) 50 { 51 u32 id; 52 53 id = __ipv6_select_ident(net, daddr, saddr); 54 return htonl(id); 55 } 56 EXPORT_SYMBOL(ipv6_select_ident); 57 58 int ip6_find_1stfragopt(struct sk_buff *skb, u8 **nexthdr) 59 { 60 unsigned int offset = sizeof(struct ipv6hdr); 61 unsigned int packet_len = skb_tail_pointer(skb) - 62 skb_network_header(skb); 63 int found_rhdr = 0; 64 *nexthdr = &ipv6_hdr(skb)->nexthdr; 65 66 while (offset <= packet_len) { 67 struct ipv6_opt_hdr *exthdr; 68 69 switch (**nexthdr) { 70 71 case NEXTHDR_HOP: 72 break; 73 case NEXTHDR_ROUTING: 74 found_rhdr = 1; 75 break; 76 case NEXTHDR_DEST: 77 #if IS_ENABLED(CONFIG_IPV6_MIP6) 78 if (ipv6_find_tlv(skb, offset, IPV6_TLV_HAO) >= 0) 79 break; 80 #endif 81 if (found_rhdr) 82 return offset; 83 break; 84 default: 85 return offset; 86 } 87 88 if (offset + sizeof(struct ipv6_opt_hdr) > packet_len) 89 return -EINVAL; 90 91 exthdr = (struct ipv6_opt_hdr *)(skb_network_header(skb) + 92 offset); 93 offset += ipv6_optlen(exthdr); 94 if (offset > IPV6_MAXPLEN) 95 return -EINVAL; 96 *nexthdr = &exthdr->nexthdr; 97 } 98 99 return -EINVAL; 100 } 101 EXPORT_SYMBOL(ip6_find_1stfragopt); 102 103 #if IS_ENABLED(CONFIG_IPV6) 104 int ip6_dst_hoplimit(struct dst_entry *dst) 105 { 106 int hoplimit = dst_metric_raw(dst, RTAX_HOPLIMIT); 107 108 rcu_read_lock(); 109 if (hoplimit == 0) { 110 struct net_device *dev = dst_dev_rcu(dst); 111 struct inet6_dev *idev; 112 113 idev = __in6_dev_get(dev); 114 if (idev) 115 hoplimit = READ_ONCE(idev->cnf.hop_limit); 116 else 117 hoplimit = READ_ONCE(dev_net(dev)->ipv6.devconf_all->hop_limit); 118 } 119 rcu_read_unlock(); 120 121 return hoplimit; 122 } 123 EXPORT_SYMBOL(ip6_dst_hoplimit); 124 #endif 125 126 int __ip6_local_out(struct net *net, struct sock *sk, struct sk_buff *skb) 127 { 128 int len; 129 130 len = skb->len - sizeof(struct ipv6hdr); 131 if (len > IPV6_MAXPLEN) 132 len = 0; 133 ipv6_hdr(skb)->payload_len = htons(len); 134 IP6CB(skb)->nhoff = offsetof(struct ipv6hdr, nexthdr); 135 136 /* if egress device is enslaved to an L3 master device pass the 137 * skb to its handler for processing 138 */ 139 skb = l3mdev_ip6_out(sk, skb); 140 if (unlikely(!skb)) 141 return 0; 142 143 skb->protocol = htons(ETH_P_IPV6); 144 145 return nf_hook(NFPROTO_IPV6, NF_INET_LOCAL_OUT, 146 net, sk, skb, NULL, skb_dst_dev(skb), 147 dst_output); 148 } 149 EXPORT_SYMBOL_GPL(__ip6_local_out); 150 151 int ip6_local_out(struct net *net, struct sock *sk, struct sk_buff *skb) 152 { 153 int err; 154 155 err = __ip6_local_out(net, sk, skb); 156 if (likely(err == 1)) 157 err = dst_output(net, sk, skb); 158 159 return err; 160 } 161 EXPORT_SYMBOL_GPL(ip6_local_out); 162