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