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authorVadim Kochan <vadim4j@gmail.com>2015-10-27 02:00:48 +0200
committerTobias Klauser <tklauser@distanz.ch>2015-10-27 11:38:20 +0100
commit830ba03c8a52c5a158e94cba463a3ccaf0e6b62f (patch)
tree0b4d70158401f3d6cfb147b124170ed02f3aaad4
parent5a59952a9ae0820b939572454374b9df03f04c44 (diff)
flowtop: Add command-line option to disable hostname lookup
Add option -n,--no-dns which allows to disable hostname lookup. Signed-off-by: Vadim Kochan <vadim4j@gmail.com> [tk: Minor wording tweaks] Signed-off-by: Tobias Klauser <tklauser@distanz.ch>
-rw-r--r--flowtop.84
-rw-r--r--flowtop.c28
2 files changed, 30 insertions, 2 deletions
diff --git a/flowtop.8 b/flowtop.8
index faa1da1..7259e1d 100644
--- a/flowtop.8
+++ b/flowtop.8
@@ -103,6 +103,10 @@ Display ICMP version 4 and version 6 flows.
.SS -S, --sctp
Display SCTP flows.
.PP
+.SS -n, --no-dns
+Don't perform hostname lookup. Only numeric addresses will be shown for flow
+endpoints.
+.PP
.SS -s, --show-src
Also show source information of the flow, not only destination information.
.PP
diff --git a/flowtop.c b/flowtop.c
index 9eda68c..d27f752 100644
--- a/flowtop.c
+++ b/flowtop.c
@@ -26,6 +26,7 @@
#include <inttypes.h>
#include <poll.h>
#include <fcntl.h>
+#include <arpa/inet.h>
#include "die.h"
#include "xmalloc.h"
@@ -110,8 +111,9 @@ static struct flow_list flow_list;
static struct sysctl_params_ctx sysctl = { -1, -1 };
static unsigned int interval = 1;
+static bool resolve_dns = true;
-static const char *short_options = "vhTUsDIS46ut:";
+static const char *short_options = "vhTUsDIS46ut:n";
static const struct option long_options[] = {
{"ipv4", no_argument, NULL, '4'},
{"ipv6", no_argument, NULL, '6'},
@@ -120,6 +122,7 @@ static const struct option long_options[] = {
{"dccp", no_argument, NULL, 'D'},
{"icmp", no_argument, NULL, 'I'},
{"sctp", no_argument, NULL, 'S'},
+ {"no-dns", no_argument, NULL, 'n'},
{"show-src", no_argument, NULL, 's'},
{"update", no_argument, NULL, 'u'},
{"interval", required_argument, NULL, 't'},
@@ -253,6 +256,7 @@ static void help(void)
" -D|--dccp Show only DCCP flows\n"
" -I|--icmp Show only ICMP/ICMPv6 flows\n"
" -S|--sctp Show only SCTP flows\n"
+ " -n|--no-dns Don't perform hostname lookup\n"
" -s|--show-src Also show source, not only dest\n"
" -u|--update Update GeoIP databases\n"
" -t|--interval <time> Refresh time in seconds (default 1s)\n"
@@ -707,12 +711,22 @@ static void flow_entry_get_extended_revdns(struct flow_entry *n,
struct sockaddr *sa;
struct hostent *hent;
+ build_bug_on(sizeof(n->rev_dns_src) != sizeof(n->rev_dns_dst));
+
switch (n->l3_proto) {
default:
bug();
case AF_INET:
flow_entry_get_sain4_obj(n, dir, &sa4);
+
+ if (!resolve_dns) {
+ inet_ntop(AF_INET, &sa4.sin_addr,
+ SELFLD(dir, rev_dns_src, rev_dns_dst),
+ sizeof(n->rev_dns_src));
+ return;
+ }
+
sa = (struct sockaddr *) &sa4;
sa_len = sizeof(sa4);
hent = gethostbyaddr(&sa4.sin_addr, sizeof(sa4.sin_addr), AF_INET);
@@ -720,13 +734,20 @@ static void flow_entry_get_extended_revdns(struct flow_entry *n,
case AF_INET6:
flow_entry_get_sain6_obj(n, dir, &sa6);
+
+ if (!resolve_dns) {
+ inet_ntop(AF_INET6, &sa6.sin6_addr,
+ SELFLD(dir, rev_dns_src, rev_dns_dst),
+ sizeof(n->rev_dns_src));
+ return;
+ }
+
sa = (struct sockaddr *) &sa6;
sa_len = sizeof(sa6);
hent = gethostbyaddr(&sa6.sin6_addr, sizeof(sa6.sin6_addr), AF_INET6);
break;
}
- build_bug_on(sizeof(n->rev_dns_src) != sizeof(n->rev_dns_dst));
getnameinfo(sa, sa_len, SELFLD(dir, rev_dns_src, rev_dns_dst),
sizeof(n->rev_dns_src), NULL, 0, NI_NUMERICHOST);
@@ -1518,6 +1539,9 @@ int main(int argc, char **argv)
case 't':
interval = strtoul(optarg, NULL, 10);
break;
+ case 'n':
+ resolve_dns = false;
+ break;
case 'h':
help();
break;