1 #include <netdb.h>
2 #include <limits.h>
3 #include <string.h>
4 #include <stdio.h>
5 #include <stdlib.h>
6 #include <sys/socket.h>
7 #include <netinet/in.h>
8 #include <arpa/inet.h>
9 #include <net/if.h>
10 #include <ctype.h>
11 #include <resolv.h>
12 #include "lookup.h"
13 #include "stdio_impl.h"
14
15 #define PTR_MAX (64 + sizeof ".in-addr.arpa")
16 #define RR_PTR 12
17
itoa(char * p,unsigned x)18 static char *itoa(char *p, unsigned x) {
19 p += 3*sizeof(int);
20 *--p = 0;
21 do {
22 *--p = '0' + x % 10;
23 x /= 10;
24 } while (x);
25 return p;
26 }
27
mkptr4(char * s,const unsigned char * ip)28 static void mkptr4(char *s, const unsigned char *ip)
29 {
30 sprintf(s, "%d.%d.%d.%d.in-addr.arpa",
31 ip[3], ip[2], ip[1], ip[0]);
32 }
33
mkptr6(char * s,const unsigned char * ip)34 static void mkptr6(char *s, const unsigned char *ip)
35 {
36 static const char xdigits[] = "0123456789abcdef";
37 int i;
38 for (i=15; i>=0; i--) {
39 *s++ = xdigits[ip[i]&15]; *s++ = '.';
40 *s++ = xdigits[ip[i]>>4]; *s++ = '.';
41 }
42 strcpy(s, "ip6.arpa");
43 }
44
reverse_hosts(char * buf,const unsigned char * a,unsigned scopeid,int family)45 static void reverse_hosts(char *buf, const unsigned char *a, unsigned scopeid, int family)
46 {
47 char line[512], *p, *z;
48 unsigned char _buf[1032], atmp[16];
49 struct address iplit;
50 FILE _f, *f = __fopen_rb_ca("/etc/hosts", &_f, _buf, sizeof _buf);
51 if (!f) return;
52 if (family == AF_INET) {
53 memcpy(atmp+12, a, 4);
54 memcpy(atmp, "\0\0\0\0\0\0\0\0\0\0\xff\xff", 12);
55 a = atmp;
56 }
57 while (fgets(line, sizeof line, f)) {
58 if ((p=strchr(line, '#'))) *p++='\n', *p=0;
59
60 for (p=line; *p && !isspace(*p); p++);
61 if (!*p) continue;
62 *p++ = 0;
63 if (__lookup_ipliteral(&iplit, line, AF_UNSPEC)<=0)
64 continue;
65
66 if (iplit.family == AF_INET) {
67 memcpy(iplit.addr+12, iplit.addr, 4);
68 memcpy(iplit.addr, "\0\0\0\0\0\0\0\0\0\0\xff\xff", 12);
69 iplit.scopeid = 0;
70 }
71
72 if (memcmp(a, iplit.addr, 16) || iplit.scopeid != scopeid)
73 continue;
74
75 for (; *p && isspace(*p); p++);
76 for (z=p; *z && !isspace(*z); z++);
77 *z = 0;
78 if (z-p < 256) {
79 memcpy(buf, p, z-p+1);
80 break;
81 }
82 }
83 __fclose_ca(f);
84 }
85
reverse_services(char * buf,int port,int dgram)86 static void reverse_services(char *buf, int port, int dgram)
87 {
88 unsigned long svport;
89 char line[128], *p, *z;
90 unsigned char _buf[1032];
91 FILE _f, *f = __fopen_rb_ca("/etc/services", &_f, _buf, sizeof _buf);
92 if (!f) return;
93 while (fgets(line, sizeof line, f)) {
94 if ((p=strchr(line, '#'))) *p++='\n', *p=0;
95
96 for (p=line; *p && !isspace(*p); p++);
97 if (!*p) continue;
98 *p++ = 0;
99 svport = strtoul(p, &z, 10);
100
101 if (svport != port || z==p) continue;
102 if (dgram && strncmp(z, "/udp", 4)) continue;
103 if (!dgram && strncmp(z, "/tcp", 4)) continue;
104 if (p-line > 32) continue;
105
106 memcpy(buf, line, p-line);
107 break;
108 }
109 __fclose_ca(f);
110 }
111
dns_parse_callback(void * c,int rr,const void * data,int len,const void * packet,int plen)112 static int dns_parse_callback(void *c, int rr, const void *data, int len, const void *packet, int plen)
113 {
114 if (rr != RR_PTR) return 0;
115 if (__dn_expand(packet, (const unsigned char *)packet + plen,
116 data, c, 256) <= 0)
117 *(char *)c = 0;
118 return 0;
119
120 }
121
getnameinfo(const struct sockaddr * restrict sa,socklen_t sl,char * restrict node,socklen_t nodelen,char * restrict serv,socklen_t servlen,int flags)122 int getnameinfo(const struct sockaddr *restrict sa, socklen_t sl,
123 char *restrict node, socklen_t nodelen,
124 char *restrict serv, socklen_t servlen,
125 int flags)
126 {
127 char ptr[PTR_MAX];
128 char buf[256], num[3*sizeof(int)+1];
129 int af = sa->sa_family;
130 unsigned char *a;
131 unsigned scopeid;
132
133 switch (af) {
134 case AF_INET:
135 a = (void *)&((struct sockaddr_in *)sa)->sin_addr;
136 if (sl < sizeof(struct sockaddr_in)) return EAI_FAMILY;
137 mkptr4(ptr, a);
138 scopeid = 0;
139 break;
140 case AF_INET6:
141 a = (void *)&((struct sockaddr_in6 *)sa)->sin6_addr;
142 if (sl < sizeof(struct sockaddr_in6)) return EAI_FAMILY;
143 if (memcmp(a, "\0\0\0\0\0\0\0\0\0\0\xff\xff", 12))
144 mkptr6(ptr, a);
145 else
146 mkptr4(ptr, a+12);
147 scopeid = ((struct sockaddr_in6 *)sa)->sin6_scope_id;
148 break;
149 default:
150 return EAI_FAMILY;
151 }
152
153 if (node && nodelen) {
154 buf[0] = 0;
155 if (!(flags & NI_NUMERICHOST)) {
156 reverse_hosts(buf, a, scopeid, af);
157 }
158 if (!*buf && !(flags & NI_NUMERICHOST)) {
159 unsigned char query[18+PTR_MAX], reply[512];
160 int qlen = __res_mkquery(0, ptr, 1, RR_PTR,
161 0, 0, 0, query, sizeof query);
162 query[3] = 0; /* don't need AD flag */
163 int rlen = __res_send(query, qlen, reply, sizeof reply);
164 buf[0] = 0;
165 if (rlen > 0) {
166 if (rlen > sizeof reply) rlen = sizeof reply;
167 __dns_parse(reply, rlen, dns_parse_callback, buf);
168 }
169 }
170 if (!*buf) {
171 if (flags & NI_NAMEREQD) return EAI_NONAME;
172 inet_ntop(af, a, buf, sizeof buf);
173 if (scopeid) {
174 char *p = 0, tmp[IF_NAMESIZE+1];
175 if (!(flags & NI_NUMERICSCOPE) &&
176 (IN6_IS_ADDR_LINKLOCAL(a) ||
177 IN6_IS_ADDR_MC_LINKLOCAL(a)))
178 p = if_indextoname(scopeid, tmp+1);
179 if (!p)
180 p = itoa(num, scopeid);
181 *--p = '%';
182 strcat(buf, p);
183 }
184 }
185 if (strlen(buf) >= nodelen) return EAI_OVERFLOW;
186 strcpy(node, buf);
187 }
188
189 if (serv && servlen) {
190 char *p = buf;
191 int port = ntohs(((struct sockaddr_in *)sa)->sin_port);
192 buf[0] = 0;
193 if (!(flags & NI_NUMERICSERV))
194 reverse_services(buf, port, flags & NI_DGRAM);
195 if (!*p)
196 p = itoa(num, port);
197 if (strlen(p) >= servlen)
198 return EAI_OVERFLOW;
199 strcpy(serv, p);
200 }
201
202 return 0;
203 }
204