[git commit] traceroute: code shrink
Denys Vlasenko
vda.linux at googlemail.com
Sat Dec 12 17:09:45 UTC 2020
commit: https://git.busybox.net/busybox/commit/?id=cc55bbef75f0e1760bb881ab59775d26b93b3afe
branch: https://git.busybox.net/busybox/commit/?id=refs/heads/master
Move init code to a separate function.
function old new delta
traceroute_init - 1203 +1203
common_traceroute_main 3391 2141 -1250
------------------------------------------------------------------------------
(add/remove: 1/0 grow/shrink: 0/1 up/down: 1203/-1250) Total: -47 bytes
Signed-off-by: Denys Vlasenko <vda.linux at googlemail.com>
---
networking/traceroute.c | 70 ++++++++++++++++++++++++++++---------------------
1 file changed, 40 insertions(+), 30 deletions(-)
diff --git a/networking/traceroute.c b/networking/traceroute.c
index 588570fcb..e6afdd8b9 100644
--- a/networking/traceroute.c
+++ b/networking/traceroute.c
@@ -394,8 +394,12 @@ struct globals {
int packlen; /* total length of packet */
int pmtu; /* Path MTU Discovery (RFC1191) */
uint32_t ident;
- uint16_t port; // 33434; /* start udp dest port # for probe packets */
- int waittime; // 5; /* time to wait for response (in seconds) */
+ uint16_t port; /* start udp dest port # for probe packets */
+ int waittime; /* time to wait for response (in seconds) */
+ int first_ttl;
+ int nprobes;
+ unsigned pausemsecs;
+ int max_ttl;
unsigned char recv_pkt[512]; /* last inbound (icmp) packet */
};
@@ -412,8 +416,6 @@ struct globals {
#define gwlist (G.gwlist )
#define INIT_G() do { \
SET_PTR_TO_GLOBALS(xzalloc(sizeof(G))); \
- port = 33434; \
- waittime = 5; \
} while (0)
#define outudp ((struct udphdr *)(outip + 1))
@@ -862,22 +864,16 @@ print_delta_ms(unsigned t1p, unsigned t2p)
printf(" %u.%03u ms", tt / 1000, tt % 1000);
}
-/*
- * Usage: [-dFIlnrvx] [-g gateway] [-i iface] [-f first_ttl]
- * [-m max_ttl] [ -p port] [-q nqueries] [-s src_addr] [-t tos]
- * [-w waittime] [-z pausemsecs] host [packetlen]"
+/* Keeping init code in a separate (not inlined!) function
+ * for stack use reduction and better register allocation in main loop.
*/
-static int
-common_traceroute_main(int op, char **argv)
+static NOINLINE void
+traceroute_init(int op, char **argv)
{
int minpacket;
#ifdef IP_TOS
int tos = 0;
#endif
- int max_ttl = 30;
- int nprobes = 3;
- int first_ttl = 1;
- unsigned pausemsecs = 0;
char *source;
char *device;
char *tos_str;
@@ -893,14 +889,16 @@ common_traceroute_main(int op, char **argv)
#else
enum { af = AF_INET };
#endif
- int ttl;
- int seq;
- struct sockaddr *lastaddr;
/* Ensure the socket fds won't be 0, 1 or 2 */
bb_sanitize_stdio();
INIT_G();
+ port = 33434;
+ waittime = 5;
+ G.first_ttl = 1;
+ G.nprobes = 3;
+ G.max_ttl = 30;
op |= getopt32(argv, "^"
OPT_STRING
@@ -919,17 +917,17 @@ common_traceroute_main(int op, char **argv)
tos = xatou_range(tos_str, 0, 255);
#endif
if (op & OPT_MAX_TTL)
- max_ttl = xatou_range(max_ttl_str, 1, 255);
+ G.max_ttl = xatou_range(max_ttl_str, 1, 255);
if (op & OPT_PORT)
port = xatou16(port_str);
if (op & OPT_NPROBES)
- nprobes = xatou_range(nprobes_str, 1, INT_MAX);
+ G.nprobes = xatou_range(nprobes_str, 1, INT_MAX);
if (op & OPT_WAITTIME)
waittime = xatou_range(waittime_str, 1, 24 * 60 * 60);
if (op & OPT_PAUSE_MS)
- pausemsecs = xatou_range(pausemsecs_str, 0, 60 * 60 * 1000);
+ G.pausemsecs = xatou_range(pausemsecs_str, 0, 60 * 60 * 1000);
if (op & OPT_FIRST_TTL)
- first_ttl = xatou_range(first_ttl_str, 1, max_ttl);
+ G.first_ttl = xatou_range(first_ttl_str, 1, G.max_ttl);
/* Process destination and optional packet size */
minpacket = sizeof(struct ip)
@@ -961,6 +959,9 @@ common_traceroute_main(int op, char **argv)
#else
dest_lsa = xhost2sockaddr(argv[0], port);
#endif
+ G.from_lsa = xmemdup(dest_lsa, LSA_LEN_SIZE + dest_lsa->len);
+ G.to = xzalloc(dest_lsa->len);
+
packlen = minpacket;
if (argv[1])
packlen = xatoul_range(argv[1], minpacket, 32 * 1024);
@@ -1102,20 +1103,28 @@ common_traceroute_main(int op, char **argv)
if (op & OPT_SOURCE)
printf(" from %s", source);
- printf(", %d hops max, %d byte packets\n", max_ttl, packlen);
+ printf(", %d hops max, %d byte packets\n", G.max_ttl, packlen);
+}
+
+static int
+common_traceroute_main(int op, char **argv)
+{
+ int ttl;
+ int seq;
+ struct sockaddr *lastaddr;
+
+ traceroute_init(op, argv);
lastaddr = xzalloc(dest_lsa->len);
- G.from_lsa = xmemdup(dest_lsa, LSA_LEN_SIZE + dest_lsa->len);
- G.to = xzalloc(dest_lsa->len);
seq = 0;
- for (ttl = first_ttl; ttl <= max_ttl; ++ttl) {
+ for (ttl = G.first_ttl; ttl <= G.max_ttl; ++ttl) {
int probe;
int unreachable = 0; /* counter */
int gotlastaddr = 0; /* flags */
int got_there = 0;
printf("%2d", ttl);
- for (probe = 0; probe < nprobes; ++probe) {
+ for (probe = 0; probe < G.nprobes; ++probe) {
int read_len;
unsigned t1;
unsigned t2;
@@ -1123,14 +1132,15 @@ common_traceroute_main(int op, char **argv)
fflush_all();
if (probe != 0)
- msleep(pausemsecs);
+ msleep(G.pausemsecs);
send_probe(++seq, ttl);
t2 = t1 = monotonic_us();
left_ms = waittime * 1000;
- /* NB: wait_for_reply() fills "G.from_lsa" and "G.to"
- * with "where it came from" and "to which local address it arrived".
+ /* NB: wait_for_reply() fills "G.from_lsa" and "G.to" with
+ * "where it came from" and "what local address it arrived to"
+ * addresses.
*/
while ((read_len = wait_for_reply(&t2, &left_ms)) != 0) {
int icmp_code;
@@ -1255,7 +1265,7 @@ common_traceroute_main(int op, char **argv)
bb_putchar('\n');
if (got_there
- || (unreachable > 0 && unreachable >= nprobes - 1)
+ || (unreachable > 0 && unreachable >= G.nprobes - 1)
) {
break;
}
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