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networking: consolidate the IP checksum code. -129 bytes.

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Signed-off-by: Baruch Siach <baruch@tkos.co.il>
Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
This commit is contained in:
Baruch Siach 2011-09-07 17:52:37 +02:00 committed by Denys Vlasenko
parent 8c84f7545c
commit e8f36330d9
7 changed files with 48 additions and 95 deletions
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1
include/libbb.h
View File

@ -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;

6
libbb/Kbuild.src
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@ -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.

32
libbb/inet_cksum.c Normal file
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@ -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;
}

31
networking/ping.c
View File

@ -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));
}

35
networking/traceroute.c
View File

@ -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;

4
networking/udhcp/dhcpc.c
View File

@ -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;
}

34
networking/udhcp/packet.c
View File

@ -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,