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

function                                             old     new   delta
nslookup_main                                       2363    2091    -272
add_ns                                               663      65    -598
------------------------------------------------------------------------------
(add/remove: 0/0 grow/shrink: 0/2 up/down: 0/-870)           Total: -870 bytes

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>

1 files changed, 70 insertions, 240 deletions

diff --git a/networking/nslookup.c b/networking/nslookup.c
index 6f8f02fc1..50d91abbc 100644
--- a/networking/nslookup.c
+++ b/networking/nslookup.c
@@ -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");