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ping: do not leak data from stack; shrink

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FANCY ping:
function                                             old     new   delta
common_ping_main                                     386    1732   +1346
sendping6                                             98      83     -15
sendping4                                            188     158     -30
ping4                                                575       -    -575
ping6                                                756       -    -756
------------------------------------------------------------------------------
(add/remove: 0/2 grow/shrink: 1/2 up/down: 1346/-1376)        Total: -30 bytes

!FANCY ping:
function                                             old     new   delta
hostname                                               4       -      -4
common_ping_main                                     566     499     -67

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
This commit is contained in:
Denys Vlasenko 2010-03-03 01:10:29 +01:00
parent 5749328b56
commit 9341fd2d30
1 changed files with 57 additions and 47 deletions
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104
networking/ping.c
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@ -43,13 +43,12 @@ enum {
DEFDATALEN = 56, DEFDATALEN = 56,
MAXIPLEN = 60, MAXIPLEN = 60,
MAXICMPLEN = 76, MAXICMPLEN = 76,
MAXPACKET = 65468,
MAX_DUP_CHK = (8 * 128), MAX_DUP_CHK = (8 * 128),
MAXWAIT = 10, MAXWAIT = 10,
PINGINTERVAL = 1, /* 1 second */ PINGINTERVAL = 1, /* 1 second */
}; };
/* common routines */ /* Common routines */
static int in_cksum(unsigned short *buf, int sz) static int in_cksum(unsigned short *buf, int sz)
{ {
@ -76,40 +75,41 @@ static int in_cksum(unsigned short *buf, int sz)
#if !ENABLE_FEATURE_FANCY_PING #if !ENABLE_FEATURE_FANCY_PING
/* simple version */ /* Simple version */
static char *hostname; struct globals {
char *hostname;
char packet[DEFDATALEN + MAXIPLEN + MAXICMPLEN];
} FIX_ALIASING;
#define G (*(struct globals*)&bb_common_bufsiz1)
#define INIT_G() do { } while (0)
static void noresp(int ign UNUSED_PARAM) static void noresp(int ign UNUSED_PARAM)
{ {
printf("No response from %s\n", hostname); printf("No response from %s\n", G.hostname);
exit(EXIT_FAILURE); exit(EXIT_FAILURE);
} }
static void ping4(len_and_sockaddr *lsa) static void ping4(len_and_sockaddr *lsa)
{ {
struct sockaddr_in pingaddr;
struct icmp *pkt; struct icmp *pkt;
int pingsock, c; int pingsock, c;
char packet[DEFDATALEN + MAXIPLEN + MAXICMPLEN];
pingsock = create_icmp_socket(); pingsock = create_icmp_socket();
pingaddr = lsa->u.sin;
pkt = (struct icmp *) packet; pkt = (struct icmp *) G.packet;
memset(pkt, 0, sizeof(packet)); memset(pkt, 0, sizeof(G.packet));
pkt->icmp_type = ICMP_ECHO; pkt->icmp_type = ICMP_ECHO;
pkt->icmp_cksum = in_cksum((unsigned short *) pkt, sizeof(packet)); pkt->icmp_cksum = in_cksum((unsigned short *) pkt, sizeof(G.packet));
c = xsendto(pingsock, packet, DEFDATALEN + ICMP_MINLEN, xsendto(pingsock, G.packet, DEFDATALEN + ICMP_MINLEN, &lsa->u.sa, lsa->len);
(struct sockaddr *) &pingaddr, sizeof(pingaddr));
/* listen for replies */ /* listen for replies */
while (1) { while (1) {
struct sockaddr_in from; struct sockaddr_in from;
socklen_t fromlen = sizeof(from); socklen_t fromlen = sizeof(from);
c = recvfrom(pingsock, packet, sizeof(packet), 0, c = recvfrom(pingsock, G.packet, sizeof(G.packet), 0,
(struct sockaddr *) &from, &fromlen); (struct sockaddr *) &from, &fromlen);
if (c < 0) { if (c < 0) {
if (errno != EINTR) if (errno != EINTR)
@ -117,9 +117,9 @@ static void ping4(len_and_sockaddr *lsa)
continue; continue;
} }
if (c >= 76) { /* ip + icmp */ if (c >= 76) { /* ip + icmp */
struct iphdr *iphdr = (struct iphdr *) packet; struct iphdr *iphdr = (struct iphdr *) G.packet;
pkt = (struct icmp *) (packet + (iphdr->ihl << 2)); /* skip ip hdr */ pkt = (struct icmp *) (G.packet + (iphdr->ihl << 2)); /* skip ip hdr */
if (pkt->icmp_type == ICMP_ECHOREPLY) if (pkt->icmp_type == ICMP_ECHOREPLY)
break; break;
} }
@ -131,31 +131,27 @@ static void ping4(len_and_sockaddr *lsa)
#if ENABLE_PING6 #if ENABLE_PING6
static void ping6(len_and_sockaddr *lsa) static void ping6(len_and_sockaddr *lsa)
{ {
struct sockaddr_in6 pingaddr;
struct icmp6_hdr *pkt; struct icmp6_hdr *pkt;
int pingsock, c; int pingsock, c;
int sockopt; int sockopt;
char packet[DEFDATALEN + MAXIPLEN + MAXICMPLEN];
pingsock = create_icmp6_socket(); pingsock = create_icmp6_socket();
pingaddr = lsa->u.sin6;
pkt = (struct icmp6_hdr *) packet; pkt = (struct icmp6_hdr *) G.packet;
memset(pkt, 0, sizeof(packet)); memset(pkt, 0, sizeof(G.packet));
pkt->icmp6_type = ICMP6_ECHO_REQUEST; pkt->icmp6_type = ICMP6_ECHO_REQUEST;
sockopt = offsetof(struct icmp6_hdr, icmp6_cksum); sockopt = offsetof(struct icmp6_hdr, icmp6_cksum);
setsockopt(pingsock, SOL_RAW, IPV6_CHECKSUM, &sockopt, sizeof(sockopt)); setsockopt(pingsock, SOL_RAW, IPV6_CHECKSUM, &sockopt, sizeof(sockopt));
c = xsendto(pingsock, packet, DEFDATALEN + sizeof (struct icmp6_hdr), xsendto(pingsock, G.packet, DEFDATALEN + sizeof(struct icmp6_hdr), &lsa->u.sa, lsa->len);
(struct sockaddr *) &pingaddr, sizeof(pingaddr));
/* listen for replies */ /* listen for replies */
while (1) { while (1) {
struct sockaddr_in6 from; struct sockaddr_in6 from;
socklen_t fromlen = sizeof(from); socklen_t fromlen = sizeof(from);
c = recvfrom(pingsock, packet, sizeof(packet), 0, c = recvfrom(pingsock, G.packet, sizeof(G.packet), 0,
(struct sockaddr *) &from, &fromlen); (struct sockaddr *) &from, &fromlen);
if (c < 0) { if (c < 0) {
if (errno != EINTR) if (errno != EINTR)
@ -163,7 +159,7 @@ static void ping6(len_and_sockaddr *lsa)
continue; continue;
} }
if (c >= ICMP_MINLEN) { /* icmp6_hdr */ if (c >= ICMP_MINLEN) { /* icmp6_hdr */
pkt = (struct icmp6_hdr *) packet; pkt = (struct icmp6_hdr *) G.packet;
if (pkt->icmp6_type == ICMP6_ECHO_REPLY) if (pkt->icmp6_type == ICMP6_ECHO_REPLY)
break; break;
} }
@ -180,6 +176,8 @@ static int common_ping_main(sa_family_t af, char **argv)
{ {
len_and_sockaddr *lsa; len_and_sockaddr *lsa;
INIT_G();
#if ENABLE_PING6 #if ENABLE_PING6
while ((++argv)[0] && argv[0][0] == '-') { while ((++argv)[0] && argv[0][0] == '-') {
if (argv[0][1] == '4') { if (argv[0][1] == '4') {
@ -196,14 +194,14 @@ static int common_ping_main(sa_family_t af, char **argv)
argv++; argv++;
#endif #endif
hostname = *argv; G.hostname = *argv;
if (!hostname) if (!G.hostname)
bb_show_usage(); bb_show_usage();
#if ENABLE_PING6 #if ENABLE_PING6
lsa = xhost_and_af2sockaddr(hostname, 0, af); lsa = xhost_and_af2sockaddr(G.hostname, 0, af);
#else #else
lsa = xhost_and_af2sockaddr(hostname, 0, AF_INET); lsa = xhost_and_af2sockaddr(G.hostname, 0, AF_INET);
#endif #endif
/* Set timer _after_ DNS resolution */ /* Set timer _after_ DNS resolution */
signal(SIGALRM, noresp); signal(SIGALRM, noresp);
@ -215,7 +213,7 @@ static int common_ping_main(sa_family_t af, char **argv)
else else
#endif #endif
ping4(lsa); ping4(lsa);
printf("%s is alive!\n", hostname); printf("%s is alive!\n", G.hostname);
return EXIT_SUCCESS; return EXIT_SUCCESS;
} }
@ -223,7 +221,7 @@ static int common_ping_main(sa_family_t af, char **argv)
#else /* FEATURE_FANCY_PING */ #else /* FEATURE_FANCY_PING */
/* full(er) version */ /* Full(er) version */
#define OPT_STRING ("qvc:s:w:W:I:4" IF_PING6("6")) #define OPT_STRING ("qvc:s:w:W:I:4" IF_PING6("6"))
enum { enum {
@ -253,6 +251,9 @@ struct globals {
unsigned deadline; unsigned deadline;
unsigned timeout; unsigned timeout;
unsigned total_secs; unsigned total_secs;
unsigned sizeof_rcv_packet;
char *rcv_packet; /* [datalen + MAXIPLEN + MAXICMPLEN] */
void *snd_packet; /* [datalen + ipv4/ipv6_const] */
const char *hostname; const char *hostname;
const char *dotted; const char *dotted;
union { union {
@ -370,19 +371,20 @@ static void sendping_tail(void (*sp)(int), const void *pkt, int size_pkt)
static void sendping4(int junk UNUSED_PARAM) static void sendping4(int junk UNUSED_PARAM)
{ {
/* +4 reserves a place for timestamp, which may end up sitting struct icmp *pkt = G.snd_packet;
* *after* packet. Saves one if() */
struct icmp *pkt = alloca(datalen + ICMP_MINLEN + 4);
memset(pkt, 0, datalen + ICMP_MINLEN + 4); //memset(pkt, 0, datalen + ICMP_MINLEN + 4); - G.snd_packet was xzalloced
pkt->icmp_type = ICMP_ECHO; pkt->icmp_type = ICMP_ECHO;
/*pkt->icmp_code = 0;*/ /*pkt->icmp_code = 0;*/
/*pkt->icmp_cksum = 0;*/ pkt->icmp_cksum = 0; /* cksum is calculated with this field set to 0 */
pkt->icmp_seq = htons(ntransmitted); /* don't ++ here, it can be a macro */ pkt->icmp_seq = htons(ntransmitted); /* don't ++ here, it can be a macro */
pkt->icmp_id = myid; pkt->icmp_id = myid;
/* We don't do hton, because we will read it back on the same machine */ /* If datalen < 4, we store timestamp _past_ the packet,
* but it's ok - we allocated 4 extra bytes in xzalloc() just in case.
*/
/*if (datalen >= 4)*/ /*if (datalen >= 4)*/
/* No hton: we'll read it back on the same machine */
*(uint32_t*)&pkt->icmp_dun = monotonic_us(); *(uint32_t*)&pkt->icmp_dun = monotonic_us();
pkt->icmp_cksum = in_cksum((unsigned short *) pkt, datalen + ICMP_MINLEN); pkt->icmp_cksum = in_cksum((unsigned short *) pkt, datalen + ICMP_MINLEN);
@ -394,7 +396,7 @@ static void sendping6(int junk UNUSED_PARAM)
{ {
struct icmp6_hdr *pkt = alloca(datalen + sizeof(struct icmp6_hdr) + 4); struct icmp6_hdr *pkt = alloca(datalen + sizeof(struct icmp6_hdr) + 4);
memset(pkt, 0, datalen + sizeof(struct icmp6_hdr) + 4); //memset(pkt, 0, datalen + sizeof(struct icmp6_hdr) + 4);
pkt->icmp6_type = ICMP6_ECHO_REQUEST; pkt->icmp6_type = ICMP6_ECHO_REQUEST;
/*pkt->icmp6_code = 0;*/ /*pkt->icmp6_code = 0;*/
/*pkt->icmp6_cksum = 0;*/ /*pkt->icmp6_cksum = 0;*/
@ -404,6 +406,8 @@ static void sendping6(int junk UNUSED_PARAM)
/*if (datalen >= 4)*/ /*if (datalen >= 4)*/
*(uint32_t*)(&pkt->icmp6_data8[4]) = monotonic_us(); *(uint32_t*)(&pkt->icmp6_data8[4]) = monotonic_us();
//TODO? pkt->icmp_cksum = in_cksum(...);
sendping_tail(sendping6, pkt, datalen + sizeof(struct icmp6_hdr)); sendping_tail(sendping6, pkt, datalen + sizeof(struct icmp6_hdr));
} }
#endif #endif
@ -561,7 +565,6 @@ static void unpack6(char *packet, int sz, /*struct sockaddr_in6 *from,*/ int hop
static void ping4(len_and_sockaddr *lsa) static void ping4(len_and_sockaddr *lsa)
{ {
char packet[datalen + MAXIPLEN + MAXICMPLEN];
int sockopt; int sockopt;
pingsock = create_icmp_socket(); pingsock = create_icmp_socket();
@ -594,14 +597,14 @@ static void ping4(len_and_sockaddr *lsa)
socklen_t fromlen = (socklen_t) sizeof(from); socklen_t fromlen = (socklen_t) sizeof(from);
int c; int c;
c = recvfrom(pingsock, packet, sizeof(packet), 0, c = recvfrom(pingsock, G.rcv_packet, G.sizeof_rcv_packet, 0,
(struct sockaddr *) &from, &fromlen); (struct sockaddr *) &from, &fromlen);
if (c < 0) { if (c < 0) {
if (errno != EINTR) if (errno != EINTR)
bb_perror_msg("recvfrom"); bb_perror_msg("recvfrom");
continue; continue;
} }
unpack4(packet, c, &from); unpack4(G.rcv_packet, c, &from);
if (pingcount && nreceived >= pingcount) if (pingcount && nreceived >= pingcount)
break; break;
} }
@ -610,7 +613,6 @@ static void ping4(len_and_sockaddr *lsa)
extern int BUG_bad_offsetof_icmp6_cksum(void); extern int BUG_bad_offsetof_icmp6_cksum(void);
static void ping6(len_and_sockaddr *lsa) static void ping6(len_and_sockaddr *lsa)
{ {
char packet[datalen + MAXIPLEN + MAXICMPLEN];
int sockopt; int sockopt;
struct msghdr msg; struct msghdr msg;
struct sockaddr_in6 from; struct sockaddr_in6 from;
@ -670,8 +672,8 @@ static void ping6(len_and_sockaddr *lsa)
msg.msg_iov = &iov; msg.msg_iov = &iov;
msg.msg_iovlen = 1; msg.msg_iovlen = 1;
msg.msg_control = control_buf; msg.msg_control = control_buf;
iov.iov_base = packet; iov.iov_base = G.rcv_packet;
iov.iov_len = sizeof(packet); iov.iov_len = G.sizeof_rcv_packet;
while (1) { while (1) {
int c; int c;
struct cmsghdr *mp; struct cmsghdr *mp;
@ -694,7 +696,7 @@ static void ping6(len_and_sockaddr *lsa)
move_from_unaligned_int(hoplimit, CMSG_DATA(mp)); move_from_unaligned_int(hoplimit, CMSG_DATA(mp));
} }
} }
unpack6(packet, c, /*&from,*/ hoplimit); unpack6(G.rcv_packet, c, /*&from,*/ hoplimit);
if (pingcount && nreceived >= pingcount) if (pingcount && nreceived >= pingcount)
break; break;
} }
@ -710,12 +712,20 @@ static void ping(len_and_sockaddr *lsa)
} }
printf(": %d data bytes\n", datalen); printf(": %d data bytes\n", datalen);
G.sizeof_rcv_packet = datalen + MAXIPLEN + MAXICMPLEN;
G.rcv_packet = xzalloc(G.sizeof_rcv_packet);
#if ENABLE_PING6 #if ENABLE_PING6
if (lsa->u.sa.sa_family == AF_INET6) if (lsa->u.sa.sa_family == AF_INET6) {
/* +4 reserves a place for timestamp, which may end up sitting
* _after_ packet. Saves one if() - see sendping4/6() */
G.snd_packet = xzalloc(datalen + sizeof(struct icmp6_hdr) + 4);
ping6(lsa); ping6(lsa);
else } else
#endif #endif
{
G.snd_packet = xzalloc(datalen + ICMP_MINLEN + 4);
ping4(lsa); ping4(lsa);
}
} }
static int common_ping_main(int opt, char **argv) static int common_ping_main(int opt, char **argv)