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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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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,