1 /* 2 * IPv6 library code, needed by static components when full IPv6 support is 3 * not configured or static. These functions are needed by GSO/GRO implementation. 4 */ 5 #include <linux/export.h> 6 #include <net/ip.h> 7 #include <net/ipv6.h> 8 #include <net/ip6_fib.h> 9 #include <net/addrconf.h> 10 #include <net/secure_seq.h> 11 #include <linux/netfilter.h> 12 13 static u32 __ipv6_select_ident(struct net *net, u32 hashrnd, 14 const struct in6_addr *dst, 15 const struct in6_addr *src) 16 { 17 u32 hash, id; 18 19 hash = __ipv6_addr_jhash(dst, hashrnd); 20 hash = __ipv6_addr_jhash(src, hash); 21 hash ^= net_hash_mix(net); 22 23 /* Treat id of 0 as unset and if we get 0 back from ip_idents_reserve, 24 * set the hight order instead thus minimizing possible future 25 * collisions. 26 */ 27 id = ip_idents_reserve(hash, 1); 28 if (unlikely(!id)) 29 id = 1 << 31; 30 31 return id; 32 } 33 34 /* This function exists only for tap drivers that must support broken 35 * clients requesting UFO without specifying an IPv6 fragment ID. 36 * 37 * This is similar to ipv6_select_ident() but we use an independent hash 38 * seed to limit information leakage. 39 * 40 * The network header must be set before calling this. 41 */ 42 __be32 ipv6_proxy_select_ident(struct net *net, struct sk_buff *skb) 43 { 44 static u32 ip6_proxy_idents_hashrnd __read_mostly; 45 struct in6_addr buf[2]; 46 struct in6_addr *addrs; 47 u32 id; 48 49 addrs = skb_header_pointer(skb, 50 skb_network_offset(skb) + 51 offsetof(struct ipv6hdr, saddr), 52 sizeof(buf), buf); 53 if (!addrs) 54 return 0; 55 56 net_get_random_once(&ip6_proxy_idents_hashrnd, 57 sizeof(ip6_proxy_idents_hashrnd)); 58 59 id = __ipv6_select_ident(net, ip6_proxy_idents_hashrnd, 60 &addrs[1], &addrs[0]); 61 return htonl(id); 62 } 63 EXPORT_SYMBOL_GPL(ipv6_proxy_select_ident); 64 65 __be32 ipv6_select_ident(struct net *net, 66 const struct in6_addr *daddr, 67 const struct in6_addr *saddr) 68 { 69 static u32 ip6_idents_hashrnd __read_mostly; 70 u32 id; 71 72 net_get_random_once(&ip6_idents_hashrnd, sizeof(ip6_idents_hashrnd)); 73 74 id = __ipv6_select_ident(net, ip6_idents_hashrnd, daddr, saddr); 75 return htonl(id); 76 } 77 EXPORT_SYMBOL(ipv6_select_ident); 78 79 int ip6_find_1stfragopt(struct sk_buff *skb, u8 **nexthdr) 80 { 81 unsigned int offset = sizeof(struct ipv6hdr); 82 unsigned int packet_len = skb_tail_pointer(skb) - 83 skb_network_header(skb); 84 int found_rhdr = 0; 85 *nexthdr = &ipv6_hdr(skb)->nexthdr; 86 87 while (offset <= packet_len) { 88 struct ipv6_opt_hdr *exthdr; 89 90 switch (**nexthdr) { 91 92 case NEXTHDR_HOP: 93 break; 94 case NEXTHDR_ROUTING: 95 found_rhdr = 1; 96 break; 97 case NEXTHDR_DEST: 98 #if IS_ENABLED(CONFIG_IPV6_MIP6) 99 if (ipv6_find_tlv(skb, offset, IPV6_TLV_HAO) >= 0) 100 break; 101 #endif 102 if (found_rhdr) 103 return offset; 104 break; 105 default: 106 return offset; 107 } 108 109 if (offset + sizeof(struct ipv6_opt_hdr) > packet_len) 110 return -EINVAL; 111 112 exthdr = (struct ipv6_opt_hdr *)(skb_network_header(skb) + 113 offset); 114 offset += ipv6_optlen(exthdr); 115 if (offset > IPV6_MAXPLEN) 116 return -EINVAL; 117 *nexthdr = &exthdr->nexthdr; 118 } 119 120 return -EINVAL; 121 } 122 EXPORT_SYMBOL(ip6_find_1stfragopt); 123 124 #if IS_ENABLED(CONFIG_IPV6) 125 int ip6_dst_hoplimit(struct dst_entry *dst) 126 { 127 int hoplimit = dst_metric_raw(dst, RTAX_HOPLIMIT); 128 if (hoplimit == 0) { 129 struct net_device *dev = dst->dev; 130 struct inet6_dev *idev; 131 132 rcu_read_lock(); 133 idev = __in6_dev_get(dev); 134 if (idev) 135 hoplimit = idev->cnf.hop_limit; 136 else 137 hoplimit = dev_net(dev)->ipv6.devconf_all->hop_limit; 138 rcu_read_unlock(); 139 } 140 return hoplimit; 141 } 142 EXPORT_SYMBOL(ip6_dst_hoplimit); 143 #endif 144 145 int __ip6_local_out(struct net *net, struct sock *sk, struct sk_buff *skb) 146 { 147 int len; 148 149 len = skb->len - sizeof(struct ipv6hdr); 150 if (len > IPV6_MAXPLEN) 151 len = 0; 152 ipv6_hdr(skb)->payload_len = htons(len); 153 IP6CB(skb)->nhoff = offsetof(struct ipv6hdr, nexthdr); 154 155 /* if egress device is enslaved to an L3 master device pass the 156 * skb to its handler for processing 157 */ 158 skb = l3mdev_ip6_out(sk, skb); 159 if (unlikely(!skb)) 160 return 0; 161 162 skb->protocol = htons(ETH_P_IPV6); 163 164 return nf_hook(NFPROTO_IPV6, NF_INET_LOCAL_OUT, 165 net, sk, skb, NULL, skb_dst(skb)->dev, 166 dst_output); 167 } 168 EXPORT_SYMBOL_GPL(__ip6_local_out); 169 170 int ip6_local_out(struct net *net, struct sock *sk, struct sk_buff *skb) 171 { 172 int err; 173 174 err = __ip6_local_out(net, sk, skb); 175 if (likely(err == 1)) 176 err = dst_output(net, sk, skb); 177 178 return err; 179 } 180 EXPORT_SYMBOL_GPL(ip6_local_out); 181