nslookup: shrink send_queries()
function old new delta rcodes 68 64 -4 nslookup_main 2007 1880 -127 ------------------------------------------------------------------------------ (add/remove: 0/0 grow/shrink: 0/2 up/down: 0/-131) Total: -131 bytes text data bss dec hex filename 926735 555 5740 933030 e3ca6 busybox_old 926525 555 5740 932820 e3bd4 busybox_unstripped Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
This commit is contained in:
Denys Vlasenko
parent
db93b21ec9
commit
71e016d806
@ -263,10 +263,10 @@ struct ns {
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struct query {
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const char *name;
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size_t qlen, rlen;
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unsigned qlen, rlen;
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unsigned latency;
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uint8_t rcode;
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unsigned char query[512], reply[512];
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unsigned long latency;
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int rcode;
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};
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static const struct {
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@ -288,23 +288,22 @@ static const struct {
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};
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static const char *const rcodes[] = {
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"NOERROR",
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"FORMERR",
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"SERVFAIL",
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"NXDOMAIN",
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"NOTIMP",
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"REFUSED",
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"YXDOMAIN",
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"YXRRSET",
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"NXRRSET",
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"NOTAUTH",
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"NOTZONE",
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"RESERVED11",
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"RESERVED12",
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"RESERVED13",
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"RESERVED14",
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"RESERVED15",
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"BADVERS"
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"NOERROR", // 0
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"FORMERR", // 1
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"SERVFAIL", // 2
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"NXDOMAIN", // 3
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"NOTIMP", // 4
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"REFUSED", // 5
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"YXDOMAIN", // 6
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"YXRRSET", // 7
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"NXRRSET", // 8
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"NOTAUTH", // 9
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"NOTZONE", // 10
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"11", // 11 not assigned
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"12", // 12 not assigned
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"13", // 13 not assigned
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"14", // 14 not assigned
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"15", // 15 not assigned
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};
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#if ENABLE_FEATURE_IPV6
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@ -518,32 +517,20 @@ static char *make_ptr(char resbuf[80], const char *addrstr)
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/*
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* Function logic borrowed & modified from musl libc, res_msend.c
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* n_queries is always > 0.
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*/
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static int send_queries(struct ns *ns, struct query *queries, int n_queries)
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static int send_queries(struct ns *ns, struct query *query, int n_queries)
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{
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len_and_sockaddr *local_lsa;
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struct pollfd pfd;
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int servfail_retry = 0;
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int n_replies = 0;
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int next_query = 0;
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int save_idx = 0;
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unsigned retry_interval;
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unsigned timeout = G.default_timeout * 1000;
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unsigned t0, t1, t2;
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unsigned tstart, tsent, tcur;
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pfd.fd = -1;
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pfd.events = POLLIN;
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retry_interval = timeout / G.default_retry;
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t0 = t2 = monotonic_ms();
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t1 = t2 - retry_interval;
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for (; t2 - t0 < timeout; t2 = monotonic_ms()) {
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if (t2 - t1 >= retry_interval) {
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int qn;
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for (qn = 0; qn < n_queries; qn++) {
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if (queries[qn].rlen)
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continue;
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if (pfd.fd < 0) {
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len_and_sockaddr *local_lsa;
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pfd.fd = xsocket_type(&local_lsa, ns->lsa->u.sa.sa_family, SOCK_DGRAM);
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/*
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* local_lsa has "null" address and port 0 now.
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@ -556,92 +543,109 @@ static int send_queries(struct ns *ns, struct query *queries, int n_queries)
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/* Make read/writes know the destination */
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xconnect(pfd.fd, &ns->lsa->u.sa, ns->lsa->len);
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ndelay_on(pfd.fd);
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}
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if (write(pfd.fd, queries[qn].query, queries[qn].qlen) < 0) {
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bb_perror_msg("write to '%s'", ns->name);
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close(pfd.fd);
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return -1; /* "no go, try next server" */
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}
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}
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t1 = t2;
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servfail_retry = 2 * n_queries;
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}
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poll_more:
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/* Wait for a response, or until time to retry */
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if (poll(&pfd, 1, t1 + retry_interval - t2) <= 0)
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continue;
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retry_interval = timeout / G.default_retry;
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tstart = tcur = monotonic_ms();
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goto send;
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while (1) {
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while (tcur - tstart < timeout) {
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int qn;
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int recvlen;
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recvlen = read(pfd.fd,
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queries[next_query].reply,
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sizeof(queries[next_query].reply)
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);
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if (tcur - tsent >= retry_interval) {
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send:
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for (qn = 0; qn < n_queries; qn++) {
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if (query[qn].rlen)
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continue;
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if (write(pfd.fd, query[qn].query, query[qn].qlen) < 0) {
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bb_perror_msg("write to '%s'", ns->name);
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n_replies = -1; /* "no go, try next server" */
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goto ret;
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}
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dbg("query %u sent\n", qn);
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}
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tsent = tcur;
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servfail_retry = 2 * n_queries;
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}
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/* read error */
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if (recvlen < 0)
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break;
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/* Wait for a response, or until time to retry */
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if (poll(&pfd, 1, retry_interval - (tcur - tsent)) <= 0)
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goto next;
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/* Ignore non-identifiable packets */
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if (recvlen < 4)
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goto poll_more;
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recvlen = read(pfd.fd, query[save_idx].reply, sizeof(query[0].reply));
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/* Error/non-identifiable packet */
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if (recvlen < 4) {
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dbg("read is too short:%d\n", recvlen);
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goto next;
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}
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/* Find which query this answer goes with, if any */
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for (qn = next_query; qn < n_queries; qn++)
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if (memcmp(queries[next_query].reply, queries[qn].query, 2) == 0)
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qn = save_idx;
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for (;;) {
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if (memcmp(query[save_idx].reply, query[qn].query, 2) == 0) {
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dbg("response matches query %u\n", qn);
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break;
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}
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if (++qn >= n_queries) {
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dbg("response does not match any query\n");
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goto next;
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}
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}
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if (qn >= n_queries || queries[qn].rlen)
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goto poll_more;
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queries[qn].rcode = queries[next_query].reply[3] & 15;
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queries[qn].latency = monotonic_ms() - t0;
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if (query[qn].rlen) {
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dbg("dropped duplicate response to query %u\n", qn);
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goto next;
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}
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ns->replies++;
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query[qn].rcode = query[save_idx].reply[3] & 15;
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dbg("query %u rcode:%s\n", qn, rcodes[query[qn].rcode]);
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/* Only accept positive or negative responses;
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* retry immediately on server failure, and ignore
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* all other codes such as refusal. */
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switch (queries[qn].rcode) {
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* all other codes such as refusal.
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*/
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switch (query[qn].rcode) {
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case 0:
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case 3:
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break;
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case 2:
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if (servfail_retry && servfail_retry--) {
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if (servfail_retry) {
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servfail_retry--;
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ns->failures++;
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write(pfd.fd, queries[qn].query, queries[qn].qlen);
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write(pfd.fd, query[qn].query, query[qn].qlen);
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dbg("query %u resent\n", qn);
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}
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/* fall through */
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default:
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next:
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tcur = monotonic_ms();
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continue;
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}
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/* Store answer */
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n_replies++;
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query[qn].rlen = recvlen;
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tcur = monotonic_ms();
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query[qn].latency = tcur - tstart;
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if (qn != save_idx) {
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/* "wrong" receive buffer, move to correct one */
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memcpy(query[qn].reply, query[save_idx].reply, recvlen);
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continue;
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}
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/* query[0..save_idx] have replies, move to next one, if exists */
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for (;;) {
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save_idx++;
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if (save_idx >= n_queries)
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goto ret; /* all are full: we have all results */
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if (!query[save_idx].rlen)
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break; /* this one is empty */
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}
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} /* while() */
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queries[qn].rlen = recvlen;
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if (qn == next_query) {
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while (next_query < n_queries) {
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if (!queries[next_query].rlen)
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break;
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next_query++;
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}
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} else {
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memcpy(queries[qn].reply, queries[next_query].reply, recvlen);
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}
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if (next_query >= n_queries)
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goto ret;
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}
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}
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ret:
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if (pfd.fd >= 0)
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close(pfd.fd);
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return n_replies;
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@ -791,12 +795,13 @@ int nslookup_main(int argc UNUSED_PARAM, char **argv)
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n_queries = 0;
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queries = NULL;
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do {
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if (types == 0) {
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/* No explicit type given, guess query type.
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* If we can convert the domain argument into a ptr (means that
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* inet_pton() could read it) we assume a PTR request, else
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* we issue A+AAAA queries and switch to an output format
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* mimicking the one of the traditional nslookup applet. */
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if (types == 0) {
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* mimicking the one of the traditional nslookup applet.
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*/
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char *ptr;
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char buf80[80];
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