From: Baruch Siach Date: Wed, 7 Sep 2011 15:52:37 +0000 (+0200) Subject: networking: consolidate the IP checksum code. -129 bytes. X-Git-Tag: 1_20_0~254 X-Git-Url: https://git.librecmc.org/?a=commitdiff_plain;h=e8f36330d9bb27f9f7e66aa6f01ff92c07d86f62;p=oweals%2Fbusybox.git networking: consolidate the IP checksum code. -129 bytes. Signed-off-by: Baruch Siach Signed-off-by: Denys Vlasenko --- diff --git a/include/libbb.h b/include/libbb.h index 1ca448930..f60f4278b 100644 --- a/include/libbb.h +++ b/include/libbb.h @@ -640,6 +640,7 @@ ssize_t recv_from_to(int fd, void *buf, size_t len, int flags, struct sockaddr *to, socklen_t sa_size) FAST_FUNC; +uint16_t inet_cksum(uint16_t *addr, int len) FAST_FUNC; char *xstrdup(const char *s) FAST_FUNC RETURNS_MALLOC; char *xstrndup(const char *s, int n) FAST_FUNC RETURNS_MALLOC; diff --git a/libbb/Kbuild.src b/libbb/Kbuild.src index 875d02456..335b34128 100644 --- a/libbb/Kbuild.src +++ b/libbb/Kbuild.src @@ -166,6 +166,12 @@ lib-$(CONFIG_IOSTAT) += get_cpu_count.o lib-$(CONFIG_MPSTAT) += get_cpu_count.o lib-$(CONFIG_POWERTOP) += get_cpu_count.o +lib-$(CONFIG_PING) += inet_cksum.o +lib-$(CONFIG_TRACEROUTE) += inet_cksum.o +lib-$(CONFIG_TRACEROUTE6) += inet_cksum.o +lib-$(CONFIG_UDHCPC) += inet_cksum.o +lib-$(CONFIG_UDHCPD) += inet_cksum.o + # We shouldn't build xregcomp.c if we don't need it - this ensures we don't # require regex.h to be in the include dir even if we don't need it thereby # allowing us to build busybox even if uclibc regex support is disabled. diff --git a/libbb/inet_cksum.c b/libbb/inet_cksum.c new file mode 100644 index 000000000..31bf8c4d9 --- /dev/null +++ b/libbb/inet_cksum.c @@ -0,0 +1,32 @@ +/* + * Checksum routine for Internet Protocol family headers (C Version) + * + * Licensed under GPLv2, see file LICENSE in this source tree. + */ + +#include "libbb.h" + +uint16_t FAST_FUNC inet_cksum(uint16_t *addr, int nleft) +{ + /* + * Our algorithm is simple, using a 32 bit accumulator, + * we add sequential 16 bit words to it, and at the end, fold + * back all the carry bits from the top 16 bits into the lower + * 16 bits. + */ + unsigned sum = 0; + while (nleft > 1) { + sum += *addr++; + nleft -= 2; + } + + /* Mop up an odd byte, if necessary */ + if (nleft) + sum += *(uint8_t*)addr; + + /* Add back carry outs from top 16 bits to low 16 bits */ + sum = (sum >> 16) + (sum & 0xffff); /* add hi 16 to low 16 */ + sum += (sum >> 16); /* add carry */ + + return (uint16_t)~sum; +} diff --git a/networking/ping.c b/networking/ping.c index efd4f210b..a1fd9dfb1 100644 --- a/networking/ping.c +++ b/networking/ping.c @@ -149,31 +149,6 @@ enum { PINGINTERVAL = 1, /* 1 second */ }; -/* Common routines */ - -static int in_cksum(unsigned short *buf, int sz) -{ - int nleft = sz; - int sum = 0; - unsigned short *w = buf; - unsigned short ans = 0; - - while (nleft > 1) { - sum += *w++; - nleft -= 2; - } - - if (nleft == 1) { - *(unsigned char *) (&ans) = *(unsigned char *) w; - sum += ans; - } - - sum = (sum >> 16) + (sum & 0xFFFF); - sum += (sum >> 16); - ans = ~sum; - return ans; -} - #if !ENABLE_FEATURE_FANCY_PING /* Simple version */ @@ -201,7 +176,7 @@ static void ping4(len_and_sockaddr *lsa) pkt = (struct icmp *) G.packet; memset(pkt, 0, sizeof(G.packet)); pkt->icmp_type = ICMP_ECHO; - pkt->icmp_cksum = in_cksum((unsigned short *) pkt, sizeof(G.packet)); + pkt->icmp_cksum = inet_cksum((uint16_t *) pkt, sizeof(G.packet)); xsendto(pingsock, G.packet, DEFDATALEN + ICMP_MINLEN, &lsa->u.sa, lsa->len); @@ -493,7 +468,7 @@ static void sendping4(int junk UNUSED_PARAM) /* No hton: we'll read it back on the same machine */ *(uint32_t*)&pkt->icmp_dun = monotonic_us(); - pkt->icmp_cksum = in_cksum((unsigned short *) pkt, datalen + ICMP_MINLEN); + pkt->icmp_cksum = inet_cksum((uint16_t *) pkt, datalen + ICMP_MINLEN); sendping_tail(sendping4, ICMP_MINLEN); } @@ -512,7 +487,7 @@ static void sendping6(int junk UNUSED_PARAM) /*if (datalen >= 4)*/ *(uint32_t*)(&pkt->icmp6_data8[4]) = monotonic_us(); - //TODO? pkt->icmp_cksum = in_cksum(...); + //TODO? pkt->icmp_cksum = inet_cksum(...); sendping_tail(sendping6, sizeof(struct icmp6_hdr)); } diff --git a/networking/traceroute.c b/networking/traceroute.c index c32103519..d197e5410 100644 --- a/networking/traceroute.c +++ b/networking/traceroute.c @@ -418,39 +418,6 @@ wait_for_reply(len_and_sockaddr *from_lsa, struct sockaddr *to, unsigned *timest return read_len; } -/* - * Checksum routine for Internet Protocol family headers (C Version) - */ -static uint16_t -in_cksum(uint16_t *addr, int len) -{ - int nleft = len; - uint16_t *w = addr; - uint16_t answer; - int sum = 0; - - /* - * Our algorithm is simple, using a 32 bit accumulator (sum), - * we add sequential 16 bit words to it, and at the end, fold - * back all the carry bits from the top 16 bits into the lower - * 16 bits. - */ - while (nleft > 1) { - sum += *w++; - nleft -= 2; - } - - /* mop up an odd byte, if necessary */ - if (nleft == 1) - sum += *(unsigned char *)w; - - /* add back carry outs from top 16 bits to low 16 bits */ - sum = (sum >> 16) + (sum & 0xffff); /* add hi 16 to low 16 */ - sum += (sum >> 16); /* add carry */ - answer = ~sum; /* truncate to 16 bits */ - return answer; -} - static void send_probe(int seq, int ttl) { @@ -477,7 +444,7 @@ send_probe(int seq, int ttl) /* Always calculate checksum for icmp packets */ outicmp->icmp_cksum = 0; - outicmp->icmp_cksum = in_cksum((uint16_t *)outicmp, + outicmp->icmp_cksum = inet_cksum((uint16_t *)outicmp, packlen - (sizeof(*outip) + optlen)); if (outicmp->icmp_cksum == 0) outicmp->icmp_cksum = 0xffff; diff --git a/networking/udhcp/dhcpc.c b/networking/udhcp/dhcpc.c index 4d755e6b8..3be09f4d7 100644 --- a/networking/udhcp/dhcpc.c +++ b/networking/udhcp/dhcpc.c @@ -739,7 +739,7 @@ static NOINLINE int udhcp_recv_raw_packet(struct dhcp_packet *dhcp_pkt, int fd) /* verify IP checksum */ check = packet.ip.check; packet.ip.check = 0; - if (check != udhcp_checksum(&packet.ip, sizeof(packet.ip))) { + if (check != inet_cksum((uint16_t *)&packet.ip, sizeof(packet.ip))) { log1("Bad IP header checksum, ignoring"); return -2; } @@ -750,7 +750,7 @@ static NOINLINE int udhcp_recv_raw_packet(struct dhcp_packet *dhcp_pkt, int fd) packet.ip.tot_len = packet.udp.len; /* yes, this is needed */ check = packet.udp.check; packet.udp.check = 0; - if (check && check != udhcp_checksum(&packet, bytes)) { + if (check && check != inet_cksum((uint16_t *)&packet, bytes)) { log1("Packet with bad UDP checksum received, ignoring"); return -2; } diff --git a/networking/udhcp/packet.c b/networking/udhcp/packet.c index 66b42c5e1..4d5ff0676 100644 --- a/networking/udhcp/packet.c +++ b/networking/udhcp/packet.c @@ -129,35 +129,6 @@ int FAST_FUNC udhcp_recv_kernel_packet(struct dhcp_packet *packet, int fd) return bytes; } -uint16_t FAST_FUNC udhcp_checksum(void *addr, int count) -{ - /* Compute Internet Checksum for "count" bytes - * beginning at location "addr". - */ - int32_t sum = 0; - uint16_t *source = (uint16_t *) addr; - - while (count > 1) { - /* This is the inner loop */ - sum += *source++; - count -= 2; - } - - /* Add left-over byte, if any */ - if (count > 0) { - /* Make sure that the left-over byte is added correctly both - * with little and big endian hosts */ - uint16_t tmp = 0; - *(uint8_t*)&tmp = *(uint8_t*)source; - sum += tmp; - } - /* Fold 32-bit sum to 16 bits */ - while (sum >> 16) - sum = (sum & 0xffff) + (sum >> 16); - - return ~sum; -} - /* Construct a ip/udp header for a packet, send packet */ int FAST_FUNC udhcp_send_raw_packet(struct dhcp_packet *dhcp_pkt, uint32_t source_nip, int source_port, @@ -212,13 +183,14 @@ int FAST_FUNC udhcp_send_raw_packet(struct dhcp_packet *dhcp_pkt, packet.udp.len = htons(UDP_DHCP_SIZE - padding); /* for UDP checksumming, ip.len is set to UDP packet len */ packet.ip.tot_len = packet.udp.len; - packet.udp.check = udhcp_checksum(&packet, IP_UDP_DHCP_SIZE - padding); + packet.udp.check = inet_cksum((uint16_t *)&packet, + IP_UDP_DHCP_SIZE - padding); /* but for sending, it is set to IP packet len */ packet.ip.tot_len = htons(IP_UDP_DHCP_SIZE - padding); packet.ip.ihl = sizeof(packet.ip) >> 2; packet.ip.version = IPVERSION; packet.ip.ttl = IPDEFTTL; - packet.ip.check = udhcp_checksum(&packet.ip, sizeof(packet.ip)); + packet.ip.check = inet_cksum((uint16_t *)&packet.ip, sizeof(packet.ip)); udhcp_dump_packet(dhcp_pkt); result = sendto(fd, &packet, IP_UDP_DHCP_SIZE - padding, /*flags:*/ 0,