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- #include <stdint.h>
- #include <byteswap.h>
- #include "uip_arch.h"
- #include "uip.h"
-
- volatile u8_t uip_acc32[4];
-
- void uip_add32 ( u8_t *op32, u16_t op16 ) {
- * ( ( uint32_t * ) uip_acc32 ) =
- htonl ( ntohl ( *( ( uint32_t * ) op32 ) ) + op16 );
- }
-
- #define BUF ((uip_tcpip_hdr *)&uip_buf[UIP_LLH_LEN])
- #define IP_PROTO_TCP 6
-
- u16_t uip_chksum(u16_t *sdata, u16_t len) {
- u16_t acc;
-
- for(acc = 0; len > 1; len -= 2) {
- acc += *sdata;
- if(acc < *sdata) {
- /* Overflow, so we add the carry to acc (i.e., increase by
- one). */
- ++acc;
- }
- ++sdata;
- }
-
- /* add up any odd byte */
- if(len == 1) {
- acc += htons(((u16_t)(*(u8_t *)sdata)) << 8);
- if(acc < htons(((u16_t)(*(u8_t *)sdata)) << 8)) {
- ++acc;
- }
- }
-
- return acc;
- }
-
- u16_t uip_ipchksum(void) {
- return uip_chksum((u16_t *)&uip_buf[UIP_LLH_LEN], 20);
- }
-
- u16_t uip_tcpchksum(void) {
- u16_t hsum, sum;
-
-
- /* Compute the checksum of the TCP header. */
- hsum = uip_chksum((u16_t *)&uip_buf[20 + UIP_LLH_LEN], 20);
-
- /* Compute the checksum of the data in the TCP packet and add it to
- the TCP header checksum. */
- sum = uip_chksum((u16_t *)uip_appdata,
- (u16_t)(((((u16_t)(BUF->len[0]) << 8) + BUF->len[1]) - 40)));
-
- if((sum += hsum) < hsum) {
- ++sum;
- }
-
- if((sum += BUF->srcipaddr[0]) < BUF->srcipaddr[0]) {
- ++sum;
- }
- if((sum += BUF->srcipaddr[1]) < BUF->srcipaddr[1]) {
- ++sum;
- }
- if((sum += BUF->destipaddr[0]) < BUF->destipaddr[0]) {
- ++sum;
- }
- if((sum += BUF->destipaddr[1]) < BUF->destipaddr[1]) {
- ++sum;
- }
- if((sum += (u16_t)htons((u16_t)IP_PROTO_TCP)) < (u16_t)htons((u16_t)IP_PROTO_TCP)) {
- ++sum;
- }
-
- hsum = (u16_t)htons((((u16_t)(BUF->len[0]) << 8) + BUF->len[1]) - 20);
-
- if((sum += hsum) < hsum) {
- ++sum;
- }
-
- return sum;
- }
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