nslookup: process replies immediately, do not store them
function old new delta nslookup_main 1837 2708 +871 parse_reply 852 - -852 ------------------------------------------------------------------------------ (add/remove: 0/1 grow/shrink: 1/0 up/down: 871/-852) Total: 19 bytes Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
This commit is contained in:
Denys Vlasenko
parent
4e73c0f659
commit
2cf75b3c81
@ -264,9 +264,10 @@ struct ns {
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struct query {
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const char *name;
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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 latency;
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// uint8_t rcode;
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unsigned char query[512];
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// unsigned char reply[512];
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};
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static const struct {
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@ -325,9 +326,14 @@ struct globals {
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G.default_timeout = 5; \
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} while (0)
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static int
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parse_reply(const unsigned char *msg, size_t len)
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enum {
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OPT_stats = (1 << 4),
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};
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static int parse_reply(const unsigned char *msg, size_t len)
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{
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HEADER *header;
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ns_msg handle;
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ns_rr rr;
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int i, n, rdlen;
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@ -335,14 +341,18 @@ parse_reply(const unsigned char *msg, size_t len)
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char astr[INET6_ADDRSTRLEN], dname[MAXDNAME];
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const unsigned char *cp;
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header = (HEADER *)msg;
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if (!header->aa)
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printf("Non-authoritative answer:\n");
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if (ns_initparse(msg, len, &handle) != 0) {
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//fprintf(stderr, "Unable to parse reply: %s\n", strerror(errno));
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//printf("Unable to parse reply: %s\n", strerror(errno));
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return -1;
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}
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for (i = 0; i < ns_msg_count(handle, ns_s_an); i++) {
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if (ns_parserr(&handle, ns_s_an, i, &rr) != 0) {
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//fprintf(stderr, "Unable to parse resource record: %s\n", strerror(errno));
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//printf("Unable to parse resource record: %s\n", strerror(errno));
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return -1;
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}
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@ -387,7 +397,7 @@ parse_reply(const unsigned char *msg, size_t len)
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if (ns_name_uncompress(ns_msg_base(handle), ns_msg_end(handle),
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ns_rr_rdata(rr), dname, sizeof(dname)) < 0
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) {
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//fprintf(stderr, "Unable to uncompress domain: %s\n", strerror(errno));
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//printf("Unable to uncompress domain: %s\n", strerror(errno));
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return -1;
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}
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printf(format, ns_rr_name(rr), dname);
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@ -395,14 +405,14 @@ parse_reply(const unsigned char *msg, size_t len)
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case ns_t_mx:
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if (rdlen < 2) {
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fprintf(stderr, "MX record too short\n");
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printf("MX record too short\n");
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return -1;
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}
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n = ns_get16(ns_rr_rdata(rr));
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if (ns_name_uncompress(ns_msg_base(handle), ns_msg_end(handle),
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ns_rr_rdata(rr) + 2, dname, sizeof(dname)) < 0
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) {
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//fprintf(stderr, "Cannot uncompress MX domain: %s\n", strerror(errno));
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//printf("Cannot uncompress MX domain: %s\n", strerror(errno));
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return -1;
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}
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printf("%s\tmail exchanger = %d %s\n", ns_rr_name(rr), n, dname);
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@ -410,7 +420,7 @@ parse_reply(const unsigned char *msg, size_t len)
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case ns_t_txt:
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if (rdlen < 1) {
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//fprintf(stderr, "TXT record too short\n");
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//printf("TXT record too short\n");
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return -1;
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}
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n = *(unsigned char *)ns_rr_rdata(rr);
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@ -433,7 +443,7 @@ parse_reply(const unsigned char *msg, size_t len)
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n = ns_name_uncompress(ns_msg_base(handle), ns_msg_end(handle),
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cp, dname, sizeof(dname));
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if (n < 0) {
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//fprintf(stderr, "Unable to uncompress domain: %s\n", strerror(errno));
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//printf("Unable to uncompress domain: %s\n", strerror(errno));
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return -1;
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}
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@ -443,7 +453,7 @@ parse_reply(const unsigned char *msg, size_t len)
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n = ns_name_uncompress(ns_msg_base(handle), ns_msg_end(handle),
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cp, dname, sizeof(dname));
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if (n < 0) {
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//fprintf(stderr, "Unable to uncompress domain: %s\n", strerror(errno));
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//printf("Unable to uncompress domain: %s\n", strerror(errno));
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return -1;
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}
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@ -513,11 +523,13 @@ static char *make_ptr(char resbuf[80], const char *addrstr)
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*/
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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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unsigned char reply[512];
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uint8_t rcode;
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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 save_idx = 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 tstart, tsent, tcur;
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@ -564,18 +576,34 @@ static int send_queries(struct ns *ns, struct query *query, int n_queries)
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if (poll(&pfd, 1, retry_interval - (tcur - tsent)) <= 0)
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goto next;
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recvlen = read(pfd.fd, query[save_idx].reply, sizeof(query[0].reply));
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recvlen = read(pfd.fd, reply, sizeof(reply));
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if (recvlen < 0) {
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bb_perror_msg("read");
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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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/* Error/non-identifiable packet */
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if (ns->replies++ == 0) {
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printf("Server:\t\t%s\n", ns->name);
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printf("Address:\t%s\n\n",
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auto_string(xmalloc_sockaddr2dotted(&ns->lsa->u.sa))
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);
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/* In "Address", bind-utils-9.11.3 show port after a hash: "1.2.3.4#53" */
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/* Should we do the same? */
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}
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/* 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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qn = save_idx;
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// qn = save_idx;
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qn = 0;
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for (;;) {
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if (memcmp(query[save_idx].reply, query[qn].query, 2) == 0) {
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if (memcmp(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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@ -590,38 +618,42 @@ static int send_queries(struct ns *ns, struct query *query, int n_queries)
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goto next;
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}
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ns->replies++;
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rcode = reply[3] & 0x0f;
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dbg("query %u rcode:%s\n", qn, rcodes[rcode]);
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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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*/
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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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/* Retry immediately on SERVFAIL */
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if (rcode == 2) {
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ns->failures++;
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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, query[qn].query, query[qn].qlen);
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dbg("query %u resent\n", qn);
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goto next;
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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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/* Process reply */
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query[qn].rlen = recvlen;
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tcur = monotonic_ms();
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#if 1
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if (option_mask32 & OPT_stats) {
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printf("Query #%d completed in %ums:\n", qn, tcur - tstart);
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}
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if (rcode != 0) {
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printf("** server can't find %s: %s\n",
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query[qn].name, rcodes[rcode]);
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} else {
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if (parse_reply(reply, recvlen) < 0)
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printf("*** Can't find %s: Parse error\n", query[qn].name);
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}
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bb_putchar('\n');
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n_replies++;
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if (n_replies >= n_queries)
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goto ret;
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#else
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//used to store replies and process them later
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query[qn].latency = tcur - tstart;
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n_replies++;
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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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@ -635,6 +667,7 @@ static int send_queries(struct ns *ns, struct query *query, int n_queries)
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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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#endif
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} /* while() */
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ret:
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@ -718,11 +751,9 @@ int nslookup_main(int argc UNUSED_PARAM, char **argv)
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llist_t *type_strings;
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int n_queries;
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unsigned types;
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int rc;
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int opts;
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enum {
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OPT_stats = (1 << 4),
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};
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int rc;
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int err;
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INIT_G();
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@ -827,61 +858,54 @@ int nslookup_main(int argc UNUSED_PARAM, char **argv)
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add_ns("127.0.0.1");
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}
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for (rc = 0; rc < G.serv_count; rc++) {
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int c = send_queries(&G.server[rc], queries, n_queries);
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if (c > 0)
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for (rc = 0; rc < G.serv_count;) {
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int c;
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c = send_queries(&G.server[rc], queries, n_queries);
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if (c > 0) {
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/* more than zero replies received */
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if (opts & OPT_stats) {
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printf("Replies:\t%d\n", G.server[rc].replies);
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printf("Failures:\t%d\n\n", G.server[rc].failures);
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}
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break;
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//FIXME: we "break" even though some queries may still be not answered, and other servers may know them?
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}
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/* c = 0: timed out waiting for replies */
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/* c < 0: error (message already printed) */
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rc++;
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if (rc >= G.serv_count) {
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fprintf(stderr,
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";; connection timed out; no servers could be reached\n\n");
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//
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// NB: bind-utils-9.11.3 behavior (all to stdout, not stderr):
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//
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// $ nslookup gmail.com 8.8.8.8
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// ;; connection timed out; no servers could be reached
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//
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// $ nslookup -s gmail.com 8.8.8.8; echo EXITCODE:$?
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// <~10 sec>
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// ;; Connection to 8.8.8.8#53(8.8.8.8) for gmail.com failed: timed out.
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// <~10 sec>
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// ;; Connection to 8.8.8.8#53(8.8.8.8) for gmail.com failed: timed out.
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// <~10 sec>
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// ;; connection timed out; no servers could be reached
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// ;; Connection to 8.8.8.8#53(8.8.8.8) for gmail.com failed: timed out.
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// <empty line>
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// EXITCODE:1
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// $ _
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printf(";; connection timed out; no servers could be reached\n\n");
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return EXIT_FAILURE;
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}
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}
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printf("Server:\t\t%s\n", G.server[rc].name);
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printf("Address:\t%s\n", xmalloc_sockaddr2dotted(&G.server[rc].lsa->u.sa));
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/* In "Address", bind-utils-9.11.3 show port after a hash: "1.2.3.4#53" */
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/* Should we do the same? */
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if (opts & OPT_stats) {
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printf("Replies:\t%d\n", G.server[rc].replies);
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printf("Failures:\t%d\n", G.server[rc].failures);
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}
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printf("\n");
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err = 0;
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for (rc = 0; rc < n_queries; rc++) {
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int c;
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if (opts & OPT_stats) {
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printf("Query #%d completed in %ums:\n", rc, queries[rc].latency);
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}
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if (queries[rc].rcode != 0) {
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printf("** server can't find %s: %s\n", queries[rc].name,
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rcodes[queries[rc].rcode]);
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continue;
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}
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c = 0;
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if (queries[rc].rlen) {
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HEADER *header;
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header = (HEADER *)queries[rc].reply;
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if (!header->aa)
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printf("Non-authoritative answer:\n");
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c = parse_reply(queries[rc].reply, queries[rc].rlen);
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}
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if (c == 0)
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if (queries[rc].rlen == 0) {
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printf("*** Can't find %s: No answer\n", queries[rc].name);
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else if (c < 0)
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printf("*** Can't find %s: Parse error\n", queries[rc].name);
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bb_putchar('\n');
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err = 1;
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}
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}
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if (err)
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bb_putchar('\n'); /* should this affect exicode too? */
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if (ENABLE_FEATURE_CLEAN_UP) {
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free(ns);
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