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>
This commit is contained in:
Denys Vlasenko 2018-04-14 17:54:24 +02:00
parent 75568354f6
commit 55bc8e8826

View File

@ -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;
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;
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
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 */
count = G.serv_count++;
p = strchr(addr, '#');
snprintf(portstr, sizeof(portstr), "%hu",
(unsigned short)(p ? strtoul(p, NULL, 10) : G.default_port));
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");