1 | #include <netdb.h>
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2 | #include <limits.h>
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3 | #include <string.h>
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4 | #include <stdio.h>
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5 | #include <sys/socket.h>
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6 | #include <netinet/in.h>
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7 | #include <arpa/inet.h>
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8 | #include <net/if.h>
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9 | #include <ctype.h>
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10 | #include "lookup.h"
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11 | #include "stdio_impl.h"
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12 |
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13 | int __dns_parse(const unsigned char *, int, int (*)(void *, int, const void *, int, const void *), void *);
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14 | int __dn_expand(const unsigned char *, const unsigned char *, const unsigned char *, char *, int);
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15 | int __res_mkquery(int, const char *, int, int, const unsigned char *, int, const unsigned char*, unsigned char *, int);
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16 | int __res_send(const unsigned char *, int, unsigned char *, int);
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17 |
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18 | #define PTR_MAX (64 + sizeof ".in-addr.arpa")
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19 | #define RR_PTR 12
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20 |
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21 | static char *itoa(char *p, unsigned x) {
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22 | p += 3*sizeof(int);
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23 | *--p = 0;
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24 | do {
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25 | *--p = '0' + x % 10;
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26 | x /= 10;
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27 | } while (x);
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28 | return p;
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29 | }
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30 |
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31 | static void mkptr4(char *s, const unsigned char *ip)
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32 | {
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33 | sprintf(s, "%d.%d.%d.%d.in-addr.arpa",
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34 | ip[3], ip[2], ip[1], ip[0]);
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35 | }
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36 |
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37 | static void mkptr6(char *s, const unsigned char *ip)
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38 | {
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39 | static const char xdigits[] = "0123456789abcdef";
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40 | int i;
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41 | for (i=15; i>=0; i--) {
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42 | *s++ = xdigits[ip[i]&15]; *s++ = '.';
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43 | *s++ = xdigits[ip[i]>>4]; *s++ = '.';
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44 | }
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45 | strcpy(s, "ip6.arpa");
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46 | }
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47 |
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48 | static void reverse_hosts(char *buf, const unsigned char *a, unsigned scopeid, int family)
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49 | {
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50 | char line[512], *p, *z;
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51 | unsigned char _buf[1032], atmp[16];
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52 | struct address iplit;
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53 | FILE _f, *f = __fopen_rb_ca("/etc/hosts", &_f, _buf, sizeof _buf);
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54 | if (!f) return;
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55 | if (family == AF_INET) {
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56 | memcpy(atmp+12, a, 4);
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57 | memcpy(atmp, "\0\0\0\0\0\0\0\0\0\0\xff\xff", 12);
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58 | a = atmp;
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59 | }
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60 | while (fgets(line, sizeof line, f)) {
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61 | if ((p=strchr(line, '#'))) *p++='\n', *p=0;
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62 |
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63 | for (p=line; *p && !isspace(*p); p++);
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64 | *p++ = 0;
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65 | if (__lookup_ipliteral(&iplit, line, AF_UNSPEC)<=0)
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66 | continue;
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67 |
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68 | if (iplit.family == AF_INET) {
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69 | memcpy(iplit.addr+12, iplit.addr, 4);
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70 | memcpy(iplit.addr, "\0\0\0\0\0\0\0\0\0\0\xff\xff", 12);
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71 | iplit.scopeid = 0;
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72 | }
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73 |
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74 | if (memcmp(a, iplit.addr, 16) || iplit.scopeid != scopeid)
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75 | continue;
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76 |
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77 | for (; *p && isspace(*p); p++);
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78 | for (z=p; *z && !isspace(*z); z++);
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79 | *z = 0;
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80 | if (z-p < 256) {
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81 | memcpy(buf, p, z-p+1);
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82 | break;
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83 | }
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84 | }
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85 | __fclose_ca(f);
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86 | }
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87 |
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88 | static void reverse_services(char *buf, int port, int dgram)
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89 | {
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90 | unsigned long svport;
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91 | char line[128], *p, *z;
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92 | unsigned char _buf[1032];
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93 | FILE _f, *f = __fopen_rb_ca("/etc/services", &_f, _buf, sizeof _buf);
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94 | if (!f) return;
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95 | while (fgets(line, sizeof line, f)) {
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96 | if ((p=strchr(line, '#'))) *p++='\n', *p=0;
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97 |
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98 | for (p=line; *p && !isspace(*p); p++);
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99 | if (!*p) continue;
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100 | *p++ = 0;
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101 | svport = strtoul(p, &z, 10);
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102 |
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103 | if (svport != port || z==p) continue;
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104 | if (dgram && strncmp(z, "/udp", 4)) continue;
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105 | if (!dgram && strncmp(z, "/tcp", 4)) continue;
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106 | if (p-line > 32) continue;
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107 |
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108 | memcpy(buf, line, p-line);
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109 | break;
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110 | }
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111 | __fclose_ca(f);
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112 | }
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113 |
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114 | static int dns_parse_callback(void *c, int rr, const void *data, int len, const void *packet)
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115 | {
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116 | if (rr != RR_PTR) return 0;
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117 | if (__dn_expand(packet, (const unsigned char *)packet + 512,
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118 | data, c, 256) <= 0)
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119 | *(char *)c = 0;
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120 | return 0;
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121 |
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122 | }
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123 |
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124 | int getnameinfo(const struct sockaddr *restrict sa, socklen_t sl,
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125 | char *restrict node, socklen_t nodelen,
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126 | char *restrict serv, socklen_t servlen,
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127 | int flags)
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128 | {
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129 | char ptr[PTR_MAX];
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130 | char buf[256], num[3*sizeof(int)+1];
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131 | int af = sa->sa_family;
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132 | unsigned char *a;
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133 | unsigned scopeid;
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134 |
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135 | switch (af) {
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136 | case AF_INET:
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137 | a = (void *)&((struct sockaddr_in *)sa)->sin_addr;
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138 | if (sl < sizeof(struct sockaddr_in)) return EAI_FAMILY;
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139 | mkptr4(ptr, a);
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140 | scopeid = 0;
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141 | break;
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142 | case AF_INET6:
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143 | a = (void *)&((struct sockaddr_in6 *)sa)->sin6_addr;
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144 | if (sl < sizeof(struct sockaddr_in6)) return EAI_FAMILY;
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145 | if (memcmp(a, "\0\0\0\0\0\0\0\0\0\0\xff\xff", 12))
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146 | mkptr6(ptr, a);
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147 | else
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148 | mkptr4(ptr, a+12);
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149 | scopeid = ((struct sockaddr_in6 *)sa)->sin6_scope_id;
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150 | break;
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151 | default:
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152 | return EAI_FAMILY;
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153 | }
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154 |
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155 | if (node && nodelen) {
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156 | buf[0] = 0;
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157 | if (!(flags & NI_NUMERICHOST)) {
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158 | reverse_hosts(buf, a, scopeid, af);
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159 | }
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160 | if (!*buf && !(flags & NI_NUMERICHOST)) {
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161 | unsigned char query[18+PTR_MAX], reply[512];
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162 | int qlen = __res_mkquery(0, ptr, 1, RR_PTR,
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163 | 0, 0, 0, query, sizeof query);
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164 | int rlen = __res_send(query, qlen, reply, sizeof reply);
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165 | buf[0] = 0;
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166 | if (rlen > 0)
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167 | __dns_parse(reply, rlen, dns_parse_callback, buf);
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168 | }
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169 | if (!*buf) {
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170 | if (flags & NI_NAMEREQD) return EAI_NONAME;
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171 | inet_ntop(af, a, buf, sizeof buf);
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172 | if (scopeid) {
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173 | char *p = 0, tmp[IF_NAMESIZE+1];
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174 | if (!(flags & NI_NUMERICSCOPE) &&
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175 | (IN6_IS_ADDR_LINKLOCAL(a) ||
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176 | IN6_IS_ADDR_MC_LINKLOCAL(a)))
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177 | p = if_indextoname(scopeid, tmp+1);
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178 | if (!p)
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179 | p = itoa(num, scopeid);
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180 | *--p = '%';
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181 | strcat(buf, p);
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182 | }
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183 | }
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184 | if (strlen(buf) >= nodelen) return EAI_OVERFLOW;
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185 | strcpy(node, buf);
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186 | }
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187 |
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188 | if (serv && servlen) {
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189 | char *p = buf;
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190 | int port = ntohs(((struct sockaddr_in *)sa)->sin_port);
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191 | buf[0] = 0;
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192 | if (!(flags & NI_NUMERICSERV))
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193 | reverse_services(buf, port, flags & NI_DGRAM);
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194 | if (!*p)
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195 | p = itoa(num, port);
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196 | if (strlen(p) >= servlen)
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197 | return EAI_OVERFLOW;
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198 | strcpy(serv, p);
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199 | }
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200 |
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201 | return 0;
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202 | }
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