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networking: consolidate the IP checksum code. -129 bytes.
Signed-off-by: Baruch Siach <baruch@tkos.co.il> Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
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@ -640,6 +640,7 @@ ssize_t recv_from_to(int fd, void *buf, size_t len, int flags,
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struct sockaddr *to,
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struct sockaddr *to,
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socklen_t sa_size) FAST_FUNC;
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socklen_t sa_size) FAST_FUNC;
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uint16_t inet_cksum(uint16_t *addr, int len) FAST_FUNC;
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char *xstrdup(const char *s) FAST_FUNC RETURNS_MALLOC;
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char *xstrdup(const char *s) FAST_FUNC RETURNS_MALLOC;
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char *xstrndup(const char *s, int n) FAST_FUNC RETURNS_MALLOC;
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char *xstrndup(const char *s, int n) FAST_FUNC RETURNS_MALLOC;
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@ -166,6 +166,12 @@ lib-$(CONFIG_IOSTAT) += get_cpu_count.o
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lib-$(CONFIG_MPSTAT) += get_cpu_count.o
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lib-$(CONFIG_MPSTAT) += get_cpu_count.o
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lib-$(CONFIG_POWERTOP) += get_cpu_count.o
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lib-$(CONFIG_POWERTOP) += get_cpu_count.o
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lib-$(CONFIG_PING) += inet_cksum.o
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lib-$(CONFIG_TRACEROUTE) += inet_cksum.o
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lib-$(CONFIG_TRACEROUTE6) += inet_cksum.o
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lib-$(CONFIG_UDHCPC) += inet_cksum.o
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lib-$(CONFIG_UDHCPD) += inet_cksum.o
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# We shouldn't build xregcomp.c if we don't need it - this ensures we don't
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# We shouldn't build xregcomp.c if we don't need it - this ensures we don't
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# require regex.h to be in the include dir even if we don't need it thereby
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# require regex.h to be in the include dir even if we don't need it thereby
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# allowing us to build busybox even if uclibc regex support is disabled.
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# allowing us to build busybox even if uclibc regex support is disabled.
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32
libbb/inet_cksum.c
Normal file
32
libbb/inet_cksum.c
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@ -0,0 +1,32 @@
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/*
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* Checksum routine for Internet Protocol family headers (C Version)
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*
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* Licensed under GPLv2, see file LICENSE in this source tree.
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*/
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#include "libbb.h"
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uint16_t FAST_FUNC inet_cksum(uint16_t *addr, int nleft)
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{
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/*
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* Our algorithm is simple, using a 32 bit accumulator,
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* we add sequential 16 bit words to it, and at the end, fold
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* back all the carry bits from the top 16 bits into the lower
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* 16 bits.
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*/
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unsigned sum = 0;
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while (nleft > 1) {
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sum += *addr++;
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nleft -= 2;
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}
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/* Mop up an odd byte, if necessary */
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if (nleft)
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sum += *(uint8_t*)addr;
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/* Add back carry outs from top 16 bits to low 16 bits */
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sum = (sum >> 16) + (sum & 0xffff); /* add hi 16 to low 16 */
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sum += (sum >> 16); /* add carry */
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return (uint16_t)~sum;
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}
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@ -149,31 +149,6 @@ enum {
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PINGINTERVAL = 1, /* 1 second */
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PINGINTERVAL = 1, /* 1 second */
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};
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};
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/* Common routines */
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static int in_cksum(unsigned short *buf, int sz)
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{
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int nleft = sz;
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int sum = 0;
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unsigned short *w = buf;
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unsigned short ans = 0;
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while (nleft > 1) {
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sum += *w++;
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nleft -= 2;
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}
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if (nleft == 1) {
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*(unsigned char *) (&ans) = *(unsigned char *) w;
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sum += ans;
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}
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sum = (sum >> 16) + (sum & 0xFFFF);
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sum += (sum >> 16);
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ans = ~sum;
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return ans;
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}
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#if !ENABLE_FEATURE_FANCY_PING
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#if !ENABLE_FEATURE_FANCY_PING
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/* Simple version */
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/* Simple version */
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@ -201,7 +176,7 @@ static void ping4(len_and_sockaddr *lsa)
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pkt = (struct icmp *) G.packet;
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pkt = (struct icmp *) G.packet;
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memset(pkt, 0, sizeof(G.packet));
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memset(pkt, 0, sizeof(G.packet));
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pkt->icmp_type = ICMP_ECHO;
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pkt->icmp_type = ICMP_ECHO;
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pkt->icmp_cksum = in_cksum((unsigned short *) pkt, sizeof(G.packet));
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pkt->icmp_cksum = inet_cksum((uint16_t *) pkt, sizeof(G.packet));
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xsendto(pingsock, G.packet, DEFDATALEN + ICMP_MINLEN, &lsa->u.sa, lsa->len);
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xsendto(pingsock, G.packet, DEFDATALEN + ICMP_MINLEN, &lsa->u.sa, lsa->len);
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@ -493,7 +468,7 @@ static void sendping4(int junk UNUSED_PARAM)
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/* No hton: we'll read it back on the same machine */
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/* No hton: we'll read it back on the same machine */
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*(uint32_t*)&pkt->icmp_dun = monotonic_us();
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*(uint32_t*)&pkt->icmp_dun = monotonic_us();
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pkt->icmp_cksum = in_cksum((unsigned short *) pkt, datalen + ICMP_MINLEN);
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pkt->icmp_cksum = inet_cksum((uint16_t *) pkt, datalen + ICMP_MINLEN);
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sendping_tail(sendping4, ICMP_MINLEN);
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sendping_tail(sendping4, ICMP_MINLEN);
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}
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}
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@ -512,7 +487,7 @@ static void sendping6(int junk UNUSED_PARAM)
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/*if (datalen >= 4)*/
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/*if (datalen >= 4)*/
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*(uint32_t*)(&pkt->icmp6_data8[4]) = monotonic_us();
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*(uint32_t*)(&pkt->icmp6_data8[4]) = monotonic_us();
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//TODO? pkt->icmp_cksum = in_cksum(...);
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//TODO? pkt->icmp_cksum = inet_cksum(...);
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sendping_tail(sendping6, sizeof(struct icmp6_hdr));
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sendping_tail(sendping6, sizeof(struct icmp6_hdr));
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}
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}
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@ -418,39 +418,6 @@ wait_for_reply(len_and_sockaddr *from_lsa, struct sockaddr *to, unsigned *timest
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return read_len;
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return read_len;
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}
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}
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/*
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* Checksum routine for Internet Protocol family headers (C Version)
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*/
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static uint16_t
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in_cksum(uint16_t *addr, int len)
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{
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int nleft = len;
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uint16_t *w = addr;
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uint16_t answer;
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int sum = 0;
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/*
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* Our algorithm is simple, using a 32 bit accumulator (sum),
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* we add sequential 16 bit words to it, and at the end, fold
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* back all the carry bits from the top 16 bits into the lower
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* 16 bits.
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*/
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while (nleft > 1) {
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sum += *w++;
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nleft -= 2;
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}
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/* mop up an odd byte, if necessary */
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if (nleft == 1)
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sum += *(unsigned char *)w;
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/* add back carry outs from top 16 bits to low 16 bits */
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sum = (sum >> 16) + (sum & 0xffff); /* add hi 16 to low 16 */
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sum += (sum >> 16); /* add carry */
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answer = ~sum; /* truncate to 16 bits */
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return answer;
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}
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static void
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static void
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send_probe(int seq, int ttl)
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send_probe(int seq, int ttl)
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{
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{
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@ -477,7 +444,7 @@ send_probe(int seq, int ttl)
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/* Always calculate checksum for icmp packets */
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/* Always calculate checksum for icmp packets */
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outicmp->icmp_cksum = 0;
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outicmp->icmp_cksum = 0;
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outicmp->icmp_cksum = in_cksum((uint16_t *)outicmp,
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outicmp->icmp_cksum = inet_cksum((uint16_t *)outicmp,
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packlen - (sizeof(*outip) + optlen));
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packlen - (sizeof(*outip) + optlen));
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if (outicmp->icmp_cksum == 0)
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if (outicmp->icmp_cksum == 0)
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outicmp->icmp_cksum = 0xffff;
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outicmp->icmp_cksum = 0xffff;
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@ -739,7 +739,7 @@ static NOINLINE int udhcp_recv_raw_packet(struct dhcp_packet *dhcp_pkt, int fd)
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/* verify IP checksum */
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/* verify IP checksum */
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check = packet.ip.check;
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check = packet.ip.check;
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packet.ip.check = 0;
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packet.ip.check = 0;
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if (check != udhcp_checksum(&packet.ip, sizeof(packet.ip))) {
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if (check != inet_cksum((uint16_t *)&packet.ip, sizeof(packet.ip))) {
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log1("Bad IP header checksum, ignoring");
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log1("Bad IP header checksum, ignoring");
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return -2;
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return -2;
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}
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}
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@ -750,7 +750,7 @@ static NOINLINE int udhcp_recv_raw_packet(struct dhcp_packet *dhcp_pkt, int fd)
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packet.ip.tot_len = packet.udp.len; /* yes, this is needed */
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packet.ip.tot_len = packet.udp.len; /* yes, this is needed */
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check = packet.udp.check;
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check = packet.udp.check;
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packet.udp.check = 0;
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packet.udp.check = 0;
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if (check && check != udhcp_checksum(&packet, bytes)) {
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if (check && check != inet_cksum((uint16_t *)&packet, bytes)) {
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log1("Packet with bad UDP checksum received, ignoring");
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log1("Packet with bad UDP checksum received, ignoring");
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return -2;
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return -2;
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}
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}
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@ -129,35 +129,6 @@ int FAST_FUNC udhcp_recv_kernel_packet(struct dhcp_packet *packet, int fd)
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return bytes;
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return bytes;
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}
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}
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uint16_t FAST_FUNC udhcp_checksum(void *addr, int count)
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{
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/* Compute Internet Checksum for "count" bytes
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* beginning at location "addr".
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*/
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int32_t sum = 0;
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uint16_t *source = (uint16_t *) addr;
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while (count > 1) {
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/* This is the inner loop */
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sum += *source++;
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count -= 2;
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}
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/* Add left-over byte, if any */
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if (count > 0) {
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/* Make sure that the left-over byte is added correctly both
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* with little and big endian hosts */
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uint16_t tmp = 0;
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*(uint8_t*)&tmp = *(uint8_t*)source;
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sum += tmp;
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}
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/* Fold 32-bit sum to 16 bits */
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while (sum >> 16)
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sum = (sum & 0xffff) + (sum >> 16);
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return ~sum;
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}
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/* Construct a ip/udp header for a packet, send packet */
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/* Construct a ip/udp header for a packet, send packet */
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int FAST_FUNC udhcp_send_raw_packet(struct dhcp_packet *dhcp_pkt,
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int FAST_FUNC udhcp_send_raw_packet(struct dhcp_packet *dhcp_pkt,
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uint32_t source_nip, int source_port,
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uint32_t source_nip, int source_port,
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@ -212,13 +183,14 @@ int FAST_FUNC udhcp_send_raw_packet(struct dhcp_packet *dhcp_pkt,
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packet.udp.len = htons(UDP_DHCP_SIZE - padding);
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packet.udp.len = htons(UDP_DHCP_SIZE - padding);
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/* for UDP checksumming, ip.len is set to UDP packet len */
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/* for UDP checksumming, ip.len is set to UDP packet len */
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packet.ip.tot_len = packet.udp.len;
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packet.ip.tot_len = packet.udp.len;
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packet.udp.check = udhcp_checksum(&packet, IP_UDP_DHCP_SIZE - padding);
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packet.udp.check = inet_cksum((uint16_t *)&packet,
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IP_UDP_DHCP_SIZE - padding);
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/* but for sending, it is set to IP packet len */
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/* but for sending, it is set to IP packet len */
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packet.ip.tot_len = htons(IP_UDP_DHCP_SIZE - padding);
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packet.ip.tot_len = htons(IP_UDP_DHCP_SIZE - padding);
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packet.ip.ihl = sizeof(packet.ip) >> 2;
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packet.ip.ihl = sizeof(packet.ip) >> 2;
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packet.ip.version = IPVERSION;
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packet.ip.version = IPVERSION;
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packet.ip.ttl = IPDEFTTL;
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packet.ip.ttl = IPDEFTTL;
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packet.ip.check = udhcp_checksum(&packet.ip, sizeof(packet.ip));
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packet.ip.check = inet_cksum((uint16_t *)&packet.ip, sizeof(packet.ip));
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udhcp_dump_packet(dhcp_pkt);
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udhcp_dump_packet(dhcp_pkt);
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result = sendto(fd, &packet, IP_UDP_DHCP_SIZE - padding, /*flags:*/ 0,
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result = sendto(fd, &packet, IP_UDP_DHCP_SIZE - padding, /*flags:*/ 0,
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