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 void 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; 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 skb_shinfo(skb)->ip6_frag_id = 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 u16 offset = sizeof(struct ipv6hdr); 82 struct ipv6_opt_hdr *exthdr = 83 (struct ipv6_opt_hdr *)(ipv6_hdr(skb) + 1); 84 unsigned int packet_len = skb_tail_pointer(skb) - 85 skb_network_header(skb); 86 int found_rhdr = 0; 87 *nexthdr = &ipv6_hdr(skb)->nexthdr; 88 89 while (offset + 1 <= packet_len) { 90 91 switch (**nexthdr) { 92 93 case NEXTHDR_HOP: 94 break; 95 case NEXTHDR_ROUTING: 96 found_rhdr = 1; 97 break; 98 case NEXTHDR_DEST: 99 #if IS_ENABLED(CONFIG_IPV6_MIP6) 100 if (ipv6_find_tlv(skb, offset, IPV6_TLV_HAO) >= 0) 101 break; 102 #endif 103 if (found_rhdr) 104 return offset; 105 break; 106 default: 107 return offset; 108 } 109 110 offset += ipv6_optlen(exthdr); 111 *nexthdr = &exthdr->nexthdr; 112 exthdr = (struct ipv6_opt_hdr *)(skb_network_header(skb) + 113 offset); 114 } 115 116 return offset; 117 } 118 EXPORT_SYMBOL(ip6_find_1stfragopt); 119 120 #if IS_ENABLED(CONFIG_IPV6) 121 int ip6_dst_hoplimit(struct dst_entry *dst) 122 { 123 int hoplimit = dst_metric_raw(dst, RTAX_HOPLIMIT); 124 if (hoplimit == 0) { 125 struct net_device *dev = dst->dev; 126 struct inet6_dev *idev; 127 128 rcu_read_lock(); 129 idev = __in6_dev_get(dev); 130 if (idev) 131 hoplimit = idev->cnf.hop_limit; 132 else 133 hoplimit = dev_net(dev)->ipv6.devconf_all->hop_limit; 134 rcu_read_unlock(); 135 } 136 return hoplimit; 137 } 138 EXPORT_SYMBOL(ip6_dst_hoplimit); 139 #endif 140 141 int __ip6_local_out(struct net *net, struct sock *sk, struct sk_buff *skb) 142 { 143 int len; 144 145 len = skb->len - sizeof(struct ipv6hdr); 146 if (len > IPV6_MAXPLEN) 147 len = 0; 148 ipv6_hdr(skb)->payload_len = htons(len); 149 IP6CB(skb)->nhoff = offsetof(struct ipv6hdr, nexthdr); 150 151 return nf_hook(NFPROTO_IPV6, NF_INET_LOCAL_OUT, 152 net, sk, skb, NULL, skb_dst(skb)->dev, 153 dst_output); 154 } 155 EXPORT_SYMBOL_GPL(__ip6_local_out); 156 157 int ip6_local_out(struct net *net, struct sock *sk, struct sk_buff *skb) 158 { 159 int err; 160 161 err = __ip6_local_out(net, sk, skb); 162 if (likely(err == 1)) 163 err = dst_output(net, sk, skb); 164 165 return err; 166 } 167 EXPORT_SYMBOL_GPL(ip6_local_out); 168