diff options
Diffstat (limited to 'contrib/netbsd-tests/lib/libc/net/h_dns_server.c')
| -rw-r--r-- | contrib/netbsd-tests/lib/libc/net/h_dns_server.c | 415 |
1 files changed, 415 insertions, 0 deletions
diff --git a/contrib/netbsd-tests/lib/libc/net/h_dns_server.c b/contrib/netbsd-tests/lib/libc/net/h_dns_server.c new file mode 100644 index 000000000000..a8f0caa41312 --- /dev/null +++ b/contrib/netbsd-tests/lib/libc/net/h_dns_server.c @@ -0,0 +1,415 @@ +/* $NetBSD: h_dns_server.c,v 1.4 2014/03/29 16:10:54 gson Exp $ */ + +/*- + * Copyright (c) 2013 The NetBSD Foundation, Inc. + * All rights reserved. + * + * This code is derived from software contributed to The NetBSD Foundation + * by Andreas Gustafsson. + * + * Redistribution and use in source and binary forms, with or without + * modification, are permitted provided that the following conditions + * are met: + * 1. Redistributions of source code must retain the above copyright + * notice, this list of conditions and the following disclaimer. + * 2. Redistributions in binary form must reproduce the above copyright + * notice, this list of conditions and the following disclaimer in the + * documentation and/or other materials provided with the distribution. + * + * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS + * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED + * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR + * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS + * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR + * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF + * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS + * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN + * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) + * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE + * POSSIBILITY OF SUCH DAMAGE. + */ + +/* + * A minimal DNS server capable of providing canned answers to the + * specific queries issued by t_hostent.sh and nothing more. + */ + +#include <sys/cdefs.h> +__RCSID("$NetBSD: h_dns_server.c,v 1.4 2014/03/29 16:10:54 gson Exp $"); + +#include <ctype.h> +#include <err.h> +#include <errno.h> +#include <fcntl.h> +#include <memory.h> +#include <stdio.h> +#include <stdlib.h> +#include <unistd.h> + +#include <sys/socket.h> + +#include <netinet/in.h> +#ifdef __NetBSD__ +#include <netinet6/in6.h> +#endif + +#ifdef __FreeBSD__ +#include <paths.h> +#endif + +union sockaddr_either { + struct sockaddr s; + struct sockaddr_in sin; + struct sockaddr_in6 sin6; +}; + +#ifdef DEBUG +#define DPRINTF(...) fprintf(stderr, __VA_ARGS__) +#else +#define DPRINTF(...) +#endif + +/* A DNS question and its corresponding answer */ + +struct dns_data { + size_t qname_size; + const char *qname; /* Wire-encode question name */ + int qtype; + size_t answer_size; + const char *answer; /* One wire-encoded answer RDATA */ +}; + +/* Convert C string constant to length + data pair */ +#define STR_DATA(s) sizeof(s) - 1, s + +/* Canned DNS queestion-answer pairs */ +struct dns_data data[] = { + /* Forward mappings */ + /* localhost IN A -> 127.0.0.1 */ + { STR_DATA("\011localhost\000"), 1, + STR_DATA("\177\000\000\001") }, + /* localhost IN AAAA -> ::1 */ + { STR_DATA("\011localhost\000"), 28, + STR_DATA("\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\001") }, + /* sixthavenue.astron.com IN A -> 38.117.134.16 */ + { STR_DATA("\013sixthavenue\006astron\003com\000"), 1, + STR_DATA("\046\165\206\020") }, + /* sixthavenue.astron.com IN AAAA -> 2620:106:3003:1f00:3e4a:92ff:fef4:e180 */ + { STR_DATA("\013sixthavenue\006astron\003com\000"), 28, + STR_DATA("\x26\x20\x01\x06\x30\x03\x1f\x00\x3e\x4a\x92\xff\xfe\xf4\xe1\x80") }, + /* Reverse mappings */ + { STR_DATA("\0011\0010\0010\003127\007in-addr\004arpa\000"), 12, + STR_DATA("\011localhost\000") }, + { STR_DATA("\0011\0010\0010\0010\0010\0010\0010\0010" + "\0010\0010\0010\0010\0010\0010\0010\0010" + "\0010\0010\0010\0010\0010\0010\0010\0010" + "\0010\0010\0010\0010\0010\0010\0010\0010" + "\003ip6\004arpa\000"), 12, + STR_DATA("\011localhost\000") }, + { STR_DATA("\00216\003134\003117\00238" + "\007in-addr\004arpa\000"), 12, + STR_DATA("\013sixthavenue\006astron\003com\000") }, + { STR_DATA("\0010\0018\0011\001e\0014\001f\001e\001f" + "\001f\001f\0012\0019\001a\0014\001e\0013" + "\0010\0010\001f\0011\0013\0010\0010\0013" + "\0016\0010\0011\0010\0010\0012\0016\0012" + "\003ip6\004arpa\000"), 12, + STR_DATA("\013sixthavenue\006astron\003com\000") }, + /* End marker */ + { STR_DATA(""), 0, STR_DATA("") } +}; + +/* + * Compare two DNS names for equality. If equal, return their + * length, and if not, return zero. Does not handle compression. + */ +static int +name_eq(const unsigned char *a, const unsigned char *b) { + const unsigned char *a_save = a; + for (;;) { + int i; + int lena = *a++; + int lenb = *b++; + if (lena != lenb) + return 0; + if (lena == 0) + return a - a_save; + for (i = 0; i < lena; i++) + if (tolower(a[i]) != tolower(b[i])) + return 0; + a += lena; + b += lena; + } +} + +#ifdef DEBUG +static char * +name2str(const void *v, char *buf, size_t buflen) { + const unsigned char *a = v; + char *b = buf; + char *eb = buf + buflen; + +#define ADDC(c) do { \ + if (b < eb) \ + *b++ = c; \ + else \ + return NULL; \ + } while (/*CONSTCOND*/0) + for (int did = 0;; did++) { + int lena = *a++; + if (lena == 0) { + ADDC('\0'); + return buf; + } + if (did) + ADDC('.'); + for (int i = 0; i < lena; i++) + ADDC(a[i]); + a += lena; + } +} +#endif + +#ifdef __FreeBSD__ +/* XXX the daemon2_* functions should be in a library */ + +int __daemon2_detach_pipe[2]; + +static int +daemon2_fork(void) +{ + int r; + int fd; + int i; + + /* + * Set up the pipe, making sure the write end does not + * get allocated one of the file descriptors that will + * be closed in daemon2_detach(). + */ + for (i = 0; i < 3; i++) { + r = pipe(__daemon2_detach_pipe); + if (r < 0) + return -1; + if (__daemon2_detach_pipe[1] <= STDERR_FILENO && + (fd = open(_PATH_DEVNULL, O_RDWR, 0)) != -1) { + (void)dup2(fd, __daemon2_detach_pipe[0]); + (void)dup2(fd, __daemon2_detach_pipe[1]); + if (fd > STDERR_FILENO) + (void)close(fd); + continue; + } + break; + } + + r = fork(); + if (r < 0) { + return -1; + } else if (r == 0) { + /* child */ + close(__daemon2_detach_pipe[0]); + return 0; + } + /* Parent */ + + (void) close(__daemon2_detach_pipe[1]); + + for (;;) { + char dummy; + r = read(__daemon2_detach_pipe[0], &dummy, 1); + if (r < 0) { + if (errno == EINTR) + continue; + _exit(1); + } else if (r == 0) { + _exit(1); + } else { /* r > 0 */ + _exit(0); + } + } +} + +static int +daemon2_detach(int nochdir, int noclose) +{ + int r; + int fd; + + if (setsid() == -1) + return -1; + + if (!nochdir) + (void)chdir("/"); + + if (!noclose && (fd = open(_PATH_DEVNULL, O_RDWR, 0)) != -1) { + (void)dup2(fd, STDIN_FILENO); + (void)dup2(fd, STDOUT_FILENO); + (void)dup2(fd, STDERR_FILENO); + if (fd > STDERR_FILENO) + (void)close(fd); + } + + while (1) { + r = write(__daemon2_detach_pipe[1], "", 1); + if (r < 0) { + if (errno == EINTR) + continue; + /* May get "broken pipe" here if parent is killed */ + return -1; + } else if (r == 0) { + /* Should not happen */ + return -1; + } else { + break; + } + } + + (void) close(__daemon2_detach_pipe[1]); + + return 0; +} +#endif + +int main(int argc, char **argv) { + int s, r, protocol; + union sockaddr_either saddr; + struct dns_data *dp; + unsigned char *p; + char pidfile_name[40]; + FILE *f; + int one = 1; +#ifdef DEBUG + char buf1[1024], buf2[1024]; +#endif + +#ifdef __FreeBSD__ + daemon2_fork(); +#endif + if (argc < 2 || ((protocol = argv[1][0]) != '4' && protocol != '6')) + errx(1, "usage: dns_server 4 | 6"); + s = socket(protocol == '4' ? PF_INET : PF_INET6, SOCK_DGRAM, IPPROTO_UDP); + if (s < 0) + err(1, "socket"); + if (protocol == '4') { + memset(&saddr.sin, 0, sizeof(saddr.sin)); + saddr.sin.sin_family = AF_INET; + saddr.sin.sin_len = sizeof(saddr.sin); + saddr.sin.sin_port = htons(53); + saddr.sin.sin_addr.s_addr = INADDR_ANY; + } else { + static struct in6_addr loopback = IN6ADDR_LOOPBACK_INIT; + memset(&saddr.sin6, 0, sizeof(saddr.sin6)); + saddr.sin6.sin6_family = AF_INET6; + saddr.sin6.sin6_len = sizeof(saddr.sin6); + saddr.sin6.sin6_port = htons(53); + saddr.sin6.sin6_addr = loopback; + } + + r = setsockopt(s, SOL_SOCKET, SO_REUSEADDR, &one, sizeof one); + if (r < 0) + err(1, "setsockopt"); + + r = bind(s, + (struct sockaddr *) &saddr, + protocol == '4' ? sizeof(struct sockaddr_in) : + sizeof(struct sockaddr_in6)); + if (r < 0) + err(1, "bind"); + + snprintf(pidfile_name, sizeof pidfile_name, + "dns_server_%c.pid", protocol); + f = fopen(pidfile_name, "w"); + fprintf(f, "%d", getpid()); + fclose(f); +#ifdef __FreeBSD__ +#ifdef DEBUG + daemon2_detach(0, 1); +#else + daemon2_detach(0, 0); +#endif +#else +#ifdef DEBUG + daemon(0, 1); +#else + daemon(0, 0); +#endif +#endif + + for (;;) { + unsigned char buf[512]; + union sockaddr_either from; + ssize_t nrecv, nsent; + socklen_t fromlen = + protocol == '4' ? sizeof(struct sockaddr_in) : + sizeof(struct sockaddr_in6); + memset(buf, 0, sizeof buf); + nrecv = recvfrom(s, buf, sizeof buf, 0, &from.s, &fromlen); + if (nrecv < 0) + err(1, "recvfrom"); + if (nrecv < 12) { + DPRINTF("Too short %zd\n", nrecv); + continue; + } + if ((buf[2] & 0x80) != 0) { + DPRINTF("Not a query 0x%x\n", buf[2]); + continue; + } + if (!(buf[4] == 0 && buf[5] == 1)) { + DPRINTF("QCOUNT is not 1 0x%x 0x%x\n", buf[4], buf[5]); + continue; /* QDCOUNT is not 1 */ + } + + for (dp = data; dp->qname_size != 0; dp++) { + int qtype, qclass; + p = buf + 12; /* Point to QNAME */ + int n = name_eq(p, (const unsigned char *) dp->qname); + if (n == 0) { + DPRINTF("no match name %s != %s\n", + name2str(p, buf1, sizeof(buf1)), + name2str(dp->qname, buf2, sizeof(buf2))); + continue; /* Name does not match */ + } + DPRINTF("match name %s\n", + name2str(p, buf1, sizeof(buf1))); + p += n; /* Skip QNAME */ + qtype = *p++ << 8; + qtype |= *p++; + if (qtype != dp->qtype) { + DPRINTF("no match name 0x%x != 0x%x\n", + qtype, dp->qtype); + continue; + } + DPRINTF("match type 0x%x\n", qtype); + qclass = *p++ << 8; + qclass |= *p++; + if (qclass != 1) { /* IN */ + DPRINTF("no match class %d != 1\n", qclass); + continue; + } + DPRINTF("match class %d\n", qclass); + goto found; + } + continue; + found: + buf[2] |= 0x80; /* QR */ + buf[3] |= 0x80; /* RA */ + memset(buf + 6, 0, 6); /* Clear ANCOUNT, NSCOUNT, ARCOUNT */ + buf[7] = 1; /* ANCOUNT */ + memcpy(p, dp->qname, dp->qname_size); + p += dp->qname_size; + *p++ = dp->qtype >> 8; + *p++ = dp->qtype & 0xFF; + *p++ = 0; + *p++ = 1; /* IN */ + memset(p, 0, 4); /* TTL = 0 */ + p += 4; + *p++ = 0; /* RDLENGTH MSB */ + *p++ = dp->answer_size; /* RDLENGTH LSB */ + memcpy(p, dp->answer, dp->answer_size); + p += dp->answer_size; + nsent = sendto(s, buf, p - buf, 0, &from.s, fromlen); + DPRINTF("sent %zd\n", nsent); + if (nsent != p - buf) + warn("sendto"); + } +} |