]>
Commit | Line | Data |
---|---|---|
7c673cae FG |
1 | #include "include/ipaddr.h" |
2 | ||
3 | #include <sys/socket.h> | |
4 | #include <arpa/inet.h> | |
5 | #include <stdlib.h> | |
6 | #include <string.h> | |
7 | ||
8 | ||
9 | static void netmask_ipv4(const struct in_addr *addr, | |
10 | unsigned int prefix_len, | |
11 | struct in_addr *out) { | |
12 | uint32_t mask; | |
13 | ||
14 | if (prefix_len >= 32) { | |
15 | // also handle 32 in this branch, because >>32 is not defined by | |
16 | // the C standards | |
17 | mask = ~uint32_t(0); | |
18 | } else { | |
19 | mask = htonl(~(~uint32_t(0) >> prefix_len)); | |
20 | } | |
21 | out->s_addr = addr->s_addr & mask; | |
22 | } | |
23 | ||
24 | ||
25 | const struct sockaddr *find_ipv4_in_subnet(const struct ifaddrs *addrs, | |
26 | const struct sockaddr_in *net, | |
27 | unsigned int prefix_len) { | |
28 | struct in_addr want, temp; | |
29 | ||
30 | netmask_ipv4(&net->sin_addr, prefix_len, &want); | |
31 | ||
32 | for (; addrs != NULL; addrs = addrs->ifa_next) { | |
33 | ||
34 | if (addrs->ifa_addr == NULL) | |
35 | continue; | |
36 | ||
37 | if (strcmp(addrs->ifa_name, "lo") == 0) | |
38 | continue; | |
39 | ||
40 | if (addrs->ifa_addr->sa_family != net->sin_family) | |
41 | continue; | |
42 | ||
43 | struct in_addr *cur = &((struct sockaddr_in*)addrs->ifa_addr)->sin_addr; | |
44 | netmask_ipv4(cur, prefix_len, &temp); | |
45 | ||
46 | if (temp.s_addr == want.s_addr) { | |
47 | return addrs->ifa_addr; | |
48 | } | |
49 | } | |
50 | ||
51 | return NULL; | |
52 | } | |
53 | ||
54 | ||
55 | static void netmask_ipv6(const struct in6_addr *addr, | |
56 | unsigned int prefix_len, | |
57 | struct in6_addr *out) { | |
58 | if (prefix_len > 128) | |
59 | prefix_len = 128; | |
60 | ||
61 | memcpy(out->s6_addr, addr->s6_addr, prefix_len/8); | |
62 | if (prefix_len < 128) | |
63 | out->s6_addr[prefix_len/8] = addr->s6_addr[prefix_len/8] & ~( 0xFF >> (prefix_len % 8) ); | |
64 | if (prefix_len/8 < 15) | |
65 | memset(out->s6_addr+prefix_len/8+1, 0, 16-prefix_len/8-1); | |
66 | } | |
67 | ||
68 | ||
69 | const struct sockaddr *find_ipv6_in_subnet(const struct ifaddrs *addrs, | |
70 | const struct sockaddr_in6 *net, | |
71 | unsigned int prefix_len) { | |
72 | struct in6_addr want, temp; | |
73 | ||
74 | netmask_ipv6(&net->sin6_addr, prefix_len, &want); | |
75 | ||
76 | for (; addrs != NULL; addrs = addrs->ifa_next) { | |
77 | ||
78 | if (addrs->ifa_addr == NULL) | |
79 | continue; | |
80 | ||
81 | if (strcmp(addrs->ifa_name, "lo") == 0) | |
82 | continue; | |
83 | ||
84 | if (addrs->ifa_addr->sa_family != net->sin6_family) | |
85 | continue; | |
86 | ||
87 | struct in6_addr *cur = &((struct sockaddr_in6*)addrs->ifa_addr)->sin6_addr; | |
88 | netmask_ipv6(cur, prefix_len, &temp); | |
89 | ||
90 | if (IN6_ARE_ADDR_EQUAL(&temp, &want)) | |
91 | return addrs->ifa_addr; | |
92 | } | |
93 | ||
94 | return NULL; | |
95 | } | |
96 | ||
97 | ||
98 | const struct sockaddr *find_ip_in_subnet(const struct ifaddrs *addrs, | |
99 | const struct sockaddr *net, | |
100 | unsigned int prefix_len) { | |
101 | switch (net->sa_family) { | |
102 | case AF_INET: | |
103 | return find_ipv4_in_subnet(addrs, (struct sockaddr_in*)net, prefix_len); | |
104 | ||
105 | case AF_INET6: | |
106 | return find_ipv6_in_subnet(addrs, (struct sockaddr_in6*)net, prefix_len); | |
107 | } | |
108 | ||
109 | return NULL; | |
110 | } | |
111 | ||
112 | ||
113 | bool parse_network(const char *s, struct sockaddr_storage *network, unsigned int *prefix_len) { | |
114 | char *slash = strchr((char*)s, '/'); | |
115 | if (!slash) { | |
116 | // no slash | |
117 | return false; | |
118 | } | |
119 | if (*(slash+1) == '\0') { | |
120 | // slash is the last character | |
121 | return false; | |
122 | } | |
123 | ||
124 | char *end; | |
125 | long int num = strtol(slash+1, &end, 10); | |
126 | if (*end != '\0') { | |
127 | // junk after the prefix_len | |
128 | return false; | |
129 | } | |
130 | if (num < 0) { | |
131 | return false; | |
132 | } | |
133 | *prefix_len = num; | |
134 | ||
135 | // copy the part before slash to get nil termination | |
136 | char *addr = (char*)alloca(slash-s + 1); | |
137 | strncpy(addr, s, slash-s); | |
138 | addr[slash-s] = '\0'; | |
139 | ||
140 | // caller expects ports etc to be zero | |
141 | memset(network, 0, sizeof(*network)); | |
142 | ||
143 | // try parsing as ipv4 | |
144 | int ok; | |
145 | ok = inet_pton(AF_INET, addr, &((struct sockaddr_in*)network)->sin_addr); | |
146 | if (ok) { | |
147 | network->ss_family = AF_INET; | |
148 | return true; | |
149 | } | |
150 | ||
151 | // try parsing as ipv6 | |
152 | ok = inet_pton(AF_INET6, addr, &((struct sockaddr_in6*)network)->sin6_addr); | |
153 | if (ok) { | |
154 | network->ss_family = AF_INET6; | |
155 | return true; | |
156 | } | |
157 | ||
158 | return false; | |
159 | } |