diff options
Diffstat (limited to 'src/network/getnameinfo.c')
| -rw-r--r-- | src/network/getnameinfo.c | 203 |
1 files changed, 203 insertions, 0 deletions
diff --git a/src/network/getnameinfo.c b/src/network/getnameinfo.c new file mode 100644 index 0000000..133c15b --- /dev/null +++ b/src/network/getnameinfo.c @@ -0,0 +1,203 @@ +#include <netdb.h> +#include <limits.h> +#include <string.h> +#include <stdio.h> +#include <stdlib.h> +#include <sys/socket.h> +#include <netinet/in.h> +#include <arpa/inet.h> +#include <net/if.h> +#include <ctype.h> +#include <resolv.h> +#include "lookup.h" +#include "stdio_impl.h" + +#define PTR_MAX (64 + sizeof ".in-addr.arpa") +#define RR_PTR 12 + +static char *itoa(char *p, unsigned x) { + p += 3*sizeof(int); + *--p = 0; + do { + *--p = '0' + x % 10; + x /= 10; + } while (x); + return p; +} + +static void mkptr4(char *s, const unsigned char *ip) +{ + sprintf(s, "%d.%d.%d.%d.in-addr.arpa", + ip[3], ip[2], ip[1], ip[0]); +} + +static void mkptr6(char *s, const unsigned char *ip) +{ + static const char xdigits[] = "0123456789abcdef"; + int i; + for (i=15; i>=0; i--) { + *s++ = xdigits[ip[i]&15]; *s++ = '.'; + *s++ = xdigits[ip[i]>>4]; *s++ = '.'; + } + strcpy(s, "ip6.arpa"); +} + +static void reverse_hosts(char *buf, const unsigned char *a, unsigned scopeid, int family) +{ + char line[512], *p, *z; + unsigned char _buf[1032], atmp[16]; + struct address iplit; + FILE _f, *f = __fopen_rb_ca("/etc/hosts", &_f, _buf, sizeof _buf); + if (!f) return; + if (family == AF_INET) { + memcpy(atmp+12, a, 4); + memcpy(atmp, "\0\0\0\0\0\0\0\0\0\0\xff\xff", 12); + a = atmp; + } + while (fgets(line, sizeof line, f)) { + if ((p=strchr(line, '#'))) *p++='\n', *p=0; + + for (p=line; *p && !isspace(*p); p++); + if (!*p) continue; + *p++ = 0; + if (__lookup_ipliteral(&iplit, line, AF_UNSPEC)<=0) + continue; + + if (iplit.family == AF_INET) { + memcpy(iplit.addr+12, iplit.addr, 4); + memcpy(iplit.addr, "\0\0\0\0\0\0\0\0\0\0\xff\xff", 12); + iplit.scopeid = 0; + } + + if (memcmp(a, iplit.addr, 16) || iplit.scopeid != scopeid) + continue; + + for (; *p && isspace(*p); p++); + for (z=p; *z && !isspace(*z); z++); + *z = 0; + if (z-p < 256) { + memcpy(buf, p, z-p+1); + break; + } + } + __fclose_ca(f); +} + +static void reverse_services(char *buf, int port, int dgram) +{ + unsigned long svport; + char line[128], *p, *z; + unsigned char _buf[1032]; + FILE _f, *f = __fopen_rb_ca("/etc/services", &_f, _buf, sizeof _buf); + if (!f) return; + while (fgets(line, sizeof line, f)) { + if ((p=strchr(line, '#'))) *p++='\n', *p=0; + + for (p=line; *p && !isspace(*p); p++); + if (!*p) continue; + *p++ = 0; + svport = strtoul(p, &z, 10); + + if (svport != port || z==p) continue; + if (dgram && strncmp(z, "/udp", 4)) continue; + if (!dgram && strncmp(z, "/tcp", 4)) continue; + if (p-line > 32) continue; + + memcpy(buf, line, p-line); + break; + } + __fclose_ca(f); +} + +static int dns_parse_callback(void *c, int rr, const void *data, int len, const void *packet, int plen) +{ + if (rr != RR_PTR) return 0; + if (__dn_expand(packet, (const unsigned char *)packet + plen, + data, c, 256) <= 0) + *(char *)c = 0; + return 0; + +} + +int getnameinfo(const struct sockaddr *restrict sa, socklen_t sl, + char *restrict node, socklen_t nodelen, + char *restrict serv, socklen_t servlen, + int flags) +{ + char ptr[PTR_MAX]; + char buf[256], num[3*sizeof(int)+1]; + int af = sa->sa_family; + unsigned char *a; + unsigned scopeid; + + switch (af) { + case AF_INET: + a = (void *)&((struct sockaddr_in *)sa)->sin_addr; + if (sl < sizeof(struct sockaddr_in)) return EAI_FAMILY; + mkptr4(ptr, a); + scopeid = 0; + break; + case AF_INET6: + a = (void *)&((struct sockaddr_in6 *)sa)->sin6_addr; + if (sl < sizeof(struct sockaddr_in6)) return EAI_FAMILY; + if (memcmp(a, "\0\0\0\0\0\0\0\0\0\0\xff\xff", 12)) + mkptr6(ptr, a); + else + mkptr4(ptr, a+12); + scopeid = ((struct sockaddr_in6 *)sa)->sin6_scope_id; + break; + default: + return EAI_FAMILY; + } + + if (node && nodelen) { + buf[0] = 0; + if (!(flags & NI_NUMERICHOST)) { + reverse_hosts(buf, a, scopeid, af); + } + if (!*buf && !(flags & NI_NUMERICHOST)) { + unsigned char query[18+PTR_MAX], reply[512]; + int qlen = __res_mkquery(0, ptr, 1, RR_PTR, + 0, 0, 0, query, sizeof query); + query[3] = 0; /* don't need AD flag */ + int rlen = __res_send(query, qlen, reply, sizeof reply); + buf[0] = 0; + if (rlen > 0) { + if (rlen > sizeof reply) rlen = sizeof reply; + __dns_parse(reply, rlen, dns_parse_callback, buf); + } + } + if (!*buf) { + if (flags & NI_NAMEREQD) return EAI_NONAME; + inet_ntop(af, a, buf, sizeof buf); + if (scopeid) { + char *p = 0, tmp[IF_NAMESIZE+1]; + if (!(flags & NI_NUMERICSCOPE) && + (IN6_IS_ADDR_LINKLOCAL(a) || + IN6_IS_ADDR_MC_LINKLOCAL(a))) + p = if_indextoname(scopeid, tmp+1); + if (!p) + p = itoa(num, scopeid); + *--p = '%'; + strcat(buf, p); + } + } + if (strlen(buf) >= nodelen) return EAI_OVERFLOW; + strcpy(node, buf); + } + + if (serv && servlen) { + char *p = buf; + int port = ntohs(((struct sockaddr_in *)sa)->sin_port); + buf[0] = 0; + if (!(flags & NI_NUMERICSERV)) + reverse_services(buf, port, flags & NI_DGRAM); + if (!*p) + p = itoa(num, port); + if (strlen(p) >= servlen) + return EAI_OVERFLOW; + strcpy(serv, p); + } + + return 0; +} |