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>

2 files changed, 5 insertions, 33 deletions

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,