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55bc8e882

Denys Vlasenko

2018-04-14

SUCCESS Duration: 144s

Subject

nslookup: usee bbox network functions instead of opne-coded mess

Binary

No binary (build failed)

Architecture & Compiler Flags

Architecture: x86_64-linux-gnu Compiler: gcc (Ubuntu 11.4.0-1ubuntu1~22.04.3) 11.4.0

—

Build Log

(log yok)

Commit Diff GitHub →

networking/nslookup.c +70 -240

networking/nslookup.c+70 -240

@@ -256,7 +256,7 @@ int nslookup_main(int argc, char **argv)

	struct ns {
	const char *name;
-	len_and_sockaddr addr;
+	len_and_sockaddr *lsa;
	int failures;
	int replies;
	};
@@ -266,7 +266,7 @@ struct query {
	size_t qlen, rlen;
	unsigned char query[512], reply[512];
	unsigned long latency;
-	int rcode, n_ns;
+	int rcode;
	};

	static const struct {
@@ -315,6 +315,8 @@ struct globals {
	unsigned default_port;
	unsigned default_retry;
	unsigned default_timeout;
+	unsigned serv_count;
+	struct ns *server;
	} FIX_ALIASING;
	#define G ((struct globals)bb_common_bufsiz1)
	#define INIT_G() do { \
@@ -480,69 +482,6 @@ parse_reply(const unsigned char msg, size_t len, int bb_style_counter)
	return i;
	}

-	static int parse_nsaddr(const char addrstr, len_and_sockaddr lsa)
-	{
-	char *hash;
-	unsigned port = G.default_port;
-	IF_FEATURE_IPV6(unsigned scope;)
-
-	dbg("%s: addrstr:'%s'\n", __func__, addrstr);
-
-	hash = strchr(addrstr, '#');
-
-	if (hash) {
-	*hash++ = '\0';
-	port = bb_strtou(hash, NULL, 10);
-	if (errno \|\| port > 65535) {
-	errno = EINVAL;
-	return -1;
-	}
-	}
-
-	#if ENABLE_FEATURE_IPV6
-	scope = 0;
-	hash = strchr(addrstr, '%');
-	if (hash) {
-	char ifname[IFNAMSIZ];
-	int i;
-
-	hash++;
-	for (i = 0; hash[i] != '\0' && hash[i] != '#'; i++) {
-	if (i >= IFNAMSIZ) {
-	errno = ENODEV;
-	return -1;
-	}
-	ifname[i] = hash[i];
-	}
-	ifname[i] = '\0';
-
-	scope = if_nametoindex(ifname);
-	if (scope == 0) {
-	errno = ENODEV;
-	return -1;
-	}
-	}
-
-	if (inet_pton(AF_INET6, addrstr, &lsa->u.sin6.sin6_addr)) {
-	lsa->u.sin6.sin6_family = AF_INET6;
-	lsa->u.sin6.sin6_port = htons(port);
-	lsa->u.sin6.sin6_scope_id = scope;
-	lsa->len = sizeof(lsa->u.sin6);
-	return 0;
-	}
-	#endif
-
-	if (inet_pton(AF_INET, addrstr, &lsa->u.sin.sin_addr)) {
-	lsa->u.sin.sin_family = AF_INET;
-	lsa->u.sin.sin_port = htons(port);
-	lsa->len = sizeof(lsa->u.sin);
-	return 0;
-	}
-
-	errno = EINVAL;
-	return -1;
-	}
-
	static char make_ptr(char resbuf[80], const char addrstr)
	{
	unsigned char addr[16];
@@ -577,104 +516,65 @@ static char make_ptr(char resbuf[80], const char addrstr)
	return NULL;
	}

-	#if ENABLE_FEATURE_IPV6
-	static void to_v4_mapped(len_and_sockaddr *a)
-	{
-	if (a->u.sa.sa_family != AF_INET)
-	return;
-
-	/* Order is important */
-	//FIXME: port?
-	memcpy(a->u.sin6.sin6_addr.s6_addr + 12, &a->u.sin.sin_addr, 4);
-	memcpy(a->u.sin6.sin6_addr.s6_addr, v4_mapped, 12);
-
-	a->u.sin6.sin6_family = AF_INET6;
-	a->u.sin6.sin6_flowinfo = 0;
-	a->u.sin6.sin6_scope_id = 0;
-	a->len = sizeof(a->u.sin6);
-	}
-	#endif
-
	/*
	* Function logic borrowed & modified from musl libc, res_msend.c
	*/
-	static int send_queries(struct ns ns, int n_ns, struct query queries, int n_queries)
+	static int send_queries(struct ns ns, struct query queries, int n_queries)
	{
-	int fd;
-	int timeout = G.default_timeout * 1000, retry_interval, servfail_retry = 0;
-	len_and_sockaddr from = { };
-	int recvlen = 0;
-	int n_replies = 0;
	struct pollfd pfd;
-	unsigned long t0, t1, t2;
-	int nn, qn, next_query = 0;
-
-	from.u.sa.sa_family = AF_INET;
-	from.len = sizeof(from.u.sin);
-	#if ENABLE_FEATURE_IPV6
-	for (nn = 0; nn < n_ns; nn++) {
-	if (ns[nn].addr.u.sa.sa_family == AF_INET6) {
-	from.u.sa.sa_family = AF_INET6;
-	from.len = sizeof(from.u.sin6);
-	break;
-	}
-	}
-	#endif
-
-	/* Get local address and open/bind a socket */
-	#if ENABLE_FEATURE_IPV6
-	fd = socket(from.u.sa.sa_family, SOCK_DGRAM\|SOCK_CLOEXEC\|SOCK_NONBLOCK, 0);
-	/* Handle case where system lacks IPv6 support */
-	if (fd < 0) {
-	if (from.u.sa.sa_family != AF_INET6 \|\| errno != EAFNOSUPPORT)
-	bb_perror_msg_and_die("socket");
-	fd = xsocket(AF_INET, SOCK_DGRAM\|SOCK_CLOEXEC\|SOCK_NONBLOCK, 0);
-	from.u.sa.sa_family = AF_INET;
-	}
-	#else
-	fd = xsocket(from.u.sa.sa_family, SOCK_DGRAM\|SOCK_CLOEXEC\|SOCK_NONBLOCK, 0);
-	#endif
-	xbind(fd, &from.u.sa, from.len);
-
-	#if ENABLE_FEATURE_IPV6
-	/* Convert any IPv4 addresses in a mixed environment to v4-mapped */
-	if (from.u.sa.sa_family == AF_INET6) {
-	setsockopt_1(fd, IPPROTO_IPV6, IPV6_V6ONLY);
-	for (nn = 0; nn < n_ns; nn++)
-	to_v4_mapped(&ns[nn].addr);
-	}
-	#endif
+	int servfail_retry = 0;
+	int n_replies = 0;
+	int next_query = 0;
+	unsigned retry_interval;
+	unsigned timeout = G.default_timeout * 1000;
+	unsigned t0, t1, t2;

-	pfd.fd = fd;
+	pfd.fd = -1;
	pfd.events = POLLIN;
+
	retry_interval = timeout / G.default_retry;
	t0 = t2 = monotonic_ms();
	t1 = t2 - retry_interval;

	for (; t2 - t0 < timeout; t2 = monotonic_ms()) {
	if (t2 - t1 >= retry_interval) {
+	int qn;
	for (qn = 0; qn < n_queries; qn++) {
	if (queries[qn].rlen)
	continue;
-
-	for (nn = 0; nn < n_ns; nn++) {
-	sendto(fd, queries[qn].query, queries[qn].qlen,
-	MSG_NOSIGNAL, &ns[nn].addr.u.sa, ns[nn].addr.len);
+	if (pfd.fd < 0) {
+	len_and_sockaddr *local_lsa;
+	pfd.fd = xsocket_type(&local_lsa, ns->lsa->u.sa.sa_family, SOCK_DGRAM);
+	/*
+	* local_lsa has "null" address and port 0 now.
+	* bind() ensures we have a particular port selected by kernel
+	* and remembered in fd, thus later recv(fd)
+	* receives only packets sent to this port.
+	*/
+	xbind(pfd.fd, &local_lsa->u.sa, local_lsa->len);
+	free(local_lsa);
+	/* Make read/writes know the destination */
+	xconnect(pfd.fd, &ns->lsa->u.sa, ns->lsa->len);
+	ndelay_on(pfd.fd);
	}
+	write(pfd.fd, queries[qn].query, queries[qn].qlen);
	}

	t1 = t2;
	servfail_retry = 2 * n_queries;
	}
-
+	poll_more:
	/* Wait for a response, or until time to retry */
	if (poll(&pfd, 1, t1 + retry_interval - t2) <= 0)
	continue;

	while (1) {
-	recvlen = recvfrom(fd, queries[next_query].reply,
-	sizeof(queries[next_query].reply), 0,
-	&from.u.sa, &from.len
+	int qn;
+	int recvlen;
+
+	recvlen = read(pfd.fd,
+	queries[next_query].reply,
+	sizeof(queries[next_query].reply)
	);

	/* read error */
@@ -683,15 +583,7 @@ static int send_queries(struct ns ns, int n_ns, struct query queries, int n_qu

	/* Ignore non-identifiable packets */
	if (recvlen < 4)
-	continue;
-
-	/* Ignore replies from addresses we didn't send to */
-	for (nn = 0; nn < n_ns; nn++)
-	if (memcmp(&from.u.sa, &ns[nn].addr.u.sa, from.len) == 0)
-	break;
-
-	if (nn >= n_ns)
-	continue;
+	goto poll_more;

	/* Find which query this answer goes with, if any */
	for (qn = next_query; qn < n_queries; qn++)
@@ -699,13 +591,12 @@ static int send_queries(struct ns ns, int n_ns, struct query queries, int n_qu
	break;

	if (qn >= n_queries \|\| queries[qn].rlen)
-	continue;
+	goto poll_more;

	queries[qn].rcode = queries[next_query].reply[3] & 15;
	queries[qn].latency = monotonic_ms() - t0;
-	queries[qn].n_ns = nn;

-	ns[nn].replies++;
+	ns->replies++;

	/* Only accept positive or negative responses;
	* retry immediately on server failure, and ignore
@@ -717,9 +608,8 @@ static int send_queries(struct ns ns, int n_ns, struct query queries, int n_qu

	case 2:
	if (servfail_retry && servfail_retry--) {
-	ns[nn].failures++;
-	sendto(fd, queries[qn].query, queries[qn].qlen,
-	MSG_NOSIGNAL, &ns[nn].addr.u.sa, ns[nn].addr.len);
+	ns->failures++;
+	write(pfd.fd, queries[qn].query, queries[qn].qlen);
	}
	/* fall through */

@@ -736,94 +626,42 @@ static int send_queries(struct ns ns, int n_ns, struct query queries, int n_qu
	while (next_query < n_queries) {
	if (!queries[next_query].rlen)
	break;
-
	next_query++;
	}
-	}
-	else {
+	} else {
	memcpy(queries[qn].reply, queries[next_query].reply, recvlen);
	}

	if (next_query >= n_queries)
-	return n_replies;
+	goto ret;
	}
	}
+	ret:
+	if (pfd.fd >= 0)
+	close(pfd.fd);

	return n_replies;
	}

-	///FIXME: use standard lsa = xhost2sockaddr(host, port) instead
-
-	static struct ns add_ns(struct ns ns, int n_ns, const char *addr)
+	static void add_ns(const char *addr)
	{
-	char portstr[sizeof("65535")], *p;
-	len_and_sockaddr a = { };
-	struct ns *tmp;
-	struct addrinfo ai, aip, hints = {
-	.ai_flags = AI_NUMERICSERV,
-	.ai_socktype = SOCK_DGRAM
-	};
+	struct ns *ns;
+	unsigned count;

	dbg("%s: addr:'%s'\n", __func__, addr);

-	if (parse_nsaddr(addr, &a)) {
-	/* Maybe we got a domain name, attempt to resolve it using the standard
-	* resolver routines */
-
-	p = strchr(addr, '#');
-	snprintf(portstr, sizeof(portstr), "%hu",
-	(unsigned short)(p ? strtoul(p, NULL, 10) : G.default_port));
+	count = G.serv_count++;

-	if (!getaddrinfo(addr, portstr, &hints, &ai)) {
-	for (aip = ai; aip; aip = aip->ai_next) {
-	if (aip->ai_addr->sa_family != AF_INET &&
-	aip->ai_addr->sa_family != AF_INET6)
-	continue;
-
-	#if ! ENABLE_FEATURE_IPV6
-	if (aip->ai_addr->sa_family != AF_INET)
-	continue;
-	#endif
-
-	tmp = realloc(ns, sizeof(ns) (*n_ns + 1));
-
-	if (!tmp)
-	return NULL;
-
-	*ns = tmp;
-
-	(ns)[n_ns].name = addr;
-	(ns)[n_ns].replies = 0;
-	(ns)[n_ns].failures = 0;
-	(ns)[n_ns].addr.len = aip->ai_addrlen;
-
-	memcpy(&(ns)[n_ns].addr.u.sa, aip->ai_addr, aip->ai_addrlen);
-
-	(*n_ns)++;
-	}
-
-	freeaddrinfo(ai);
-
-	return &(ns)[n_ns];
-	}
-
-	return NULL;
-	}
-
-	tmp = xrealloc(ns, sizeof(ns) (*n_ns + 1));
-	*ns = tmp;
-
-	(ns)[n_ns].addr = a;
-	(ns)[n_ns].name = addr;
-	(ns)[n_ns].replies = 0;
-	(ns)[n_ns].failures = 0;
-
-	return &(ns)[(n_ns)++];
+	G.server = xrealloc_vector(G.server, /8=2^3:/ 3, count);
+	ns = &G.server[count];
+	ns->name = addr;
+	ns->lsa = xhost2sockaddr(addr, 53);
+	/ns->replies = 0; - already is /
+	/ns->failures = 0; - already is /
	}

-	static int parse_resolvconf(struct ns *ns, int n_ns)
+	static void parse_resolvconf(void)
	{
-	int prev_n_ns = *n_ns;
	FILE *resolv;

	resolv = fopen("/etc/resolv.conf", "r");
@@ -841,16 +679,11 @@ static int parse_resolvconf(struct ns *ns, int n_ns)
	if (!p)
	continue;

-	if (!add_ns(ns, n_ns, xstrdup(p))) {
-	free(p);
-	break;
-	}
+	add_ns(xstrdup(p));
	}

	fclose(resolv);
	}
-
-	return *n_ns - prev_n_ns;
	}

	static struct query add_query(struct query queries, int n_queries,
@@ -913,7 +746,7 @@ int nslookup_main(int argc UNUSED_PARAM, char **argv)
	struct ns *ns;
	struct query *queries;
	llist_t *type_strings;
-	int n_ns, n_queries;
+	int n_queries;
	int bb_style_counter = 0;
	unsigned types;
	int rc;
@@ -1018,40 +851,37 @@ int nslookup_main(int argc UNUSED_PARAM, char **argv)
	} while (argv[0] && argv[1]);

	/* Use given DNS server if present */
-	n_ns = 0;
-	ns = NULL;
	if (argv[0]) {
-	if (!add_ns(&ns, &n_ns, argv[0]))
-	bb_error_msg_and_die("invalid NS server address \"%s\"", argv[0]);
+	add_ns(argv[0]);
	} else {
-	parse_resolvconf(&ns, &n_ns);
+	parse_resolvconf();
	/* Fall back to localhost if we could not find NS in resolv.conf */
-	if (n_ns == 0)
-	add_ns(&ns, &n_ns, "127.0.0.1");
+	if (G.serv_count == 0)
+	add_ns("127.0.0.1");
	}

-	for (rc = 0; rc < n_ns; rc++) {
-	int c = send_queries(&ns[rc], 1, queries, n_queries);
+	for (rc = 0; rc < G.serv_count; rc++) {
+	int c = send_queries(&G.server[rc], queries, n_queries);
	if (c < 0)
	bb_perror_msg_and_die("can't send queries");
	if (c > 0)
	break;
	rc++;
-	if (rc >= n_ns) {
+	if (rc >= G.serv_count) {
	fprintf(stderr,
	";; connection timed out; no servers could be reached\n\n");
	return EXIT_FAILURE;
	}
	}

-	printf("Server:\t\t%s\n", ns[rc].name);
+	printf("Server:\t\t%s\n", G.server[rc].name);
	{
	char buf[SIZEOF_SAL2STR_BUF];
-	printf("Address:\t%s\n", sal2str(buf, &ns[rc].addr));
+	printf("Address:\t%s\n", sal2str(buf, G.server[rc].lsa));
	}
	if (opts & OPT_stats) {
-	printf("Replies:\t%d\n", ns[rc].replies);
-	printf("Failures:\t%d\n", ns[rc].failures);
+	printf("Replies:\t%d\n", G.server[rc].replies);
+	printf("Failures:\t%d\n", G.server[rc].failures);
	}
	printf("\n");