/* New version of ip_checksum, notice this version does not change it into
* network order. It is useful to keep it in host order for further processing
*/
uint16_t __ip_checksum(void *dataptr, unsigned int len, uint32_t sum)
{
uint8_t *pb = (uint8_t *)dataptr;
uint16_t *ps, t = 0;
int odd = ((uintptr_t)pb & 1);
/* Get aligned to uint16_t */
// this means pb started on some weird address..
// but in our world this should never happen.. since the payload should always be aligned..
// right..
if (odd && len > 0) {
// change the second half of t to what pb is
// and advance pb
((uint8_t *)&t)[1] = *pb++;
len--;
}
/* Add the bulk of the data */
ps = (uint16_t *)(void *)pb;
while (len > 1) {
sum += *ps++;
len -= 2;
}
/* Consume left-over byte, if any */
if (len > 0) {
((uint8_t *)&t)[0] = *(uint8_t *)ps;
}
/* Add end bytes */
sum += t;
/* Fold 32-bit sum to 16 bits
calling this twice is propably faster than if statements... */
sum = FOLD_U32T(sum);
sum = FOLD_U32T(sum);
/* Swap if alignment was odd */
if (odd) {
sum = byte_swap16(sum);
}
return (uint16_t)sum;
}
/** Add a checksum of newly added data to the segment */
static void ICACHE_FLASH_ATTR
tcp_seg_add_chksum(u16_t chksum, u16_t len, u16_t *seg_chksum,
u8_t *seg_chksum_swapped) {
u32_t helper;
/* add chksum to old chksum and fold to u16_t */
helper = chksum + *seg_chksum;
chksum = FOLD_U32T(helper);
if ((len & 1) != 0) {
*seg_chksum_swapped = 1 - *seg_chksum_swapped;
chksum = SWAP_BYTES_IN_WORD(chksum);
}
*seg_chksum = chksum;
}
/* ip addresses need to be network order, protolen and proto are HO */
uint16_t inet_chksum_pseudo(struct pbuf *p, uint32_t src, uint32_t dest, uint8_t proto, uint16_t proto_len) {
uint32_t acc;
uint32_t addr;
struct pbuf *q;
uint8_t swapped;
acc = 0;
swapped = 0;
/* iterate through all pbuf in chain */
for(q = p; q != NULL; q = STAILQ_NEXT(q, next)) {
acc += __ip_checksum(q->payload, q->len, 0);
acc = FOLD_U32T(acc);
if (q->len % 2 != 0) {
swapped = 1 - swapped;
acc = byte_swap16(acc);
}
}
if (swapped) {
acc = byte_swap16(acc);
}
addr = (src);
acc += (addr & 0xffffUL);
acc += ((addr >> 16) & 0xffffUL);
addr = (dest);
acc += (addr & 0xffffUL);
acc += ((addr >> 16) & 0xffffUL);
acc += (uint32_t)htons((uint16_t)proto);
acc += (uint32_t)htons(proto_len);
/* Fold 32-bit sum to 16 bits
calling this twice is propably faster than if statements... */
acc = FOLD_U32T(acc);
acc = FOLD_U32T(acc);
return (uint16_t)~(acc & 0xffffUL);
}
