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 12 u32 __ipv6_select_ident(u32 hashrnd, struct in6_addr *dst, struct in6_addr *src) 13 { 14 u32 hash, id; 15 16 hash = __ipv6_addr_jhash(dst, hashrnd); 17 hash = __ipv6_addr_jhash(src, hash); 18 19 /* Treat id of 0 as unset and if we get 0 back from ip_idents_reserve, 20 * set the hight order instead thus minimizing possible future 21 * collisions. 22 */ 23 id = ip_idents_reserve(hash, 1); 24 if (unlikely(!id)) 25 id = 1 << 31; 26 27 return id; 28 } 29 30 /* This function exists only for tap drivers that must support broken 31 * clients requesting UFO without specifying an IPv6 fragment ID. 32 * 33 * This is similar to ipv6_select_ident() but we use an independent hash 34 * seed to limit information leakage. 35 * 36 * The network header must be set before calling this. 37 */ 38 void ipv6_proxy_select_ident(struct sk_buff *skb) 39 { 40 static u32 ip6_proxy_idents_hashrnd __read_mostly; 41 struct in6_addr buf[2]; 42 struct in6_addr *addrs; 43 u32 id; 44 45 addrs = skb_header_pointer(skb, 46 skb_network_offset(skb) + 47 offsetof(struct ipv6hdr, saddr), 48 sizeof(buf), buf); 49 if (!addrs) 50 return; 51 52 net_get_random_once(&ip6_proxy_idents_hashrnd, 53 sizeof(ip6_proxy_idents_hashrnd)); 54 55 id = __ipv6_select_ident(ip6_proxy_idents_hashrnd, 56 &addrs[1], &addrs[0]); 57 skb_shinfo(skb)->ip6_frag_id = id; 58 } 59 EXPORT_SYMBOL_GPL(ipv6_proxy_select_ident); 60 61 void ipv6_select_ident(struct frag_hdr *fhdr, struct rt6_info *rt) 62 { 63 static u32 ip6_idents_hashrnd __read_mostly; 64 u32 id; 65 66 net_get_random_once(&ip6_idents_hashrnd, sizeof(ip6_idents_hashrnd)); 67 68 id = __ipv6_select_ident(ip6_idents_hashrnd, &rt->rt6i_dst.addr, 69 &rt->rt6i_src.addr); 70 fhdr->identification = htonl(id); 71 } 72 EXPORT_SYMBOL(ipv6_select_ident); 73 74 int ip6_find_1stfragopt(struct sk_buff *skb, u8 **nexthdr) 75 { 76 u16 offset = sizeof(struct ipv6hdr); 77 struct ipv6_opt_hdr *exthdr = 78 (struct ipv6_opt_hdr *)(ipv6_hdr(skb) + 1); 79 unsigned int packet_len = skb_tail_pointer(skb) - 80 skb_network_header(skb); 81 int found_rhdr = 0; 82 *nexthdr = &ipv6_hdr(skb)->nexthdr; 83 84 while (offset + 1 <= packet_len) { 85 86 switch (**nexthdr) { 87 88 case NEXTHDR_HOP: 89 break; 90 case NEXTHDR_ROUTING: 91 found_rhdr = 1; 92 break; 93 case NEXTHDR_DEST: 94 #if IS_ENABLED(CONFIG_IPV6_MIP6) 95 if (ipv6_find_tlv(skb, offset, IPV6_TLV_HAO) >= 0) 96 break; 97 #endif 98 if (found_rhdr) 99 return offset; 100 break; 101 default: 102 return offset; 103 } 104 105 offset += ipv6_optlen(exthdr); 106 *nexthdr = &exthdr->nexthdr; 107 exthdr = (struct ipv6_opt_hdr *)(skb_network_header(skb) + 108 offset); 109 } 110 111 return offset; 112 } 113 EXPORT_SYMBOL(ip6_find_1stfragopt); 114 115 #if IS_ENABLED(CONFIG_IPV6) 116 int ip6_dst_hoplimit(struct dst_entry *dst) 117 { 118 int hoplimit = dst_metric_raw(dst, RTAX_HOPLIMIT); 119 if (hoplimit == 0) { 120 struct net_device *dev = dst->dev; 121 struct inet6_dev *idev; 122 123 rcu_read_lock(); 124 idev = __in6_dev_get(dev); 125 if (idev) 126 hoplimit = idev->cnf.hop_limit; 127 else 128 hoplimit = dev_net(dev)->ipv6.devconf_all->hop_limit; 129 rcu_read_unlock(); 130 } 131 return hoplimit; 132 } 133 EXPORT_SYMBOL(ip6_dst_hoplimit); 134 #endif 135 136 int __ip6_local_out(struct sk_buff *skb) 137 { 138 int len; 139 140 len = skb->len - sizeof(struct ipv6hdr); 141 if (len > IPV6_MAXPLEN) 142 len = 0; 143 ipv6_hdr(skb)->payload_len = htons(len); 144 IP6CB(skb)->nhoff = offsetof(struct ipv6hdr, nexthdr); 145 146 return nf_hook(NFPROTO_IPV6, NF_INET_LOCAL_OUT, skb, NULL, 147 skb_dst(skb)->dev, dst_output); 148 } 149 EXPORT_SYMBOL_GPL(__ip6_local_out); 150 151 int ip6_local_out(struct sk_buff *skb) 152 { 153 int err; 154 155 err = __ip6_local_out(skb); 156 if (likely(err == 1)) 157 err = dst_output(skb); 158 159 return err; 160 } 161 EXPORT_SYMBOL_GPL(ip6_local_out); 162