From: Denys Vlasenko Date: Sat, 14 Apr 2018 15:54:24 +0000 (+0200) Subject: nslookup: usee bbox network functions instead of opne-coded mess X-Git-Tag: 1_29_0~78 X-Git-Url: https://git.librecmc.org/?a=commitdiff_plain;h=55bc8e8826df8cf5c342f57e513d10ee6c632838;p=oweals%2Fbusybox.git 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 --- 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");