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#include "inet.h"
#include "endian.h"
#include <string.h>
void prne_netmask_from_cidr (uint8_t *out, size_t cidr) {
size_t shft = 7;
while (cidr >= 8) {
*out = 0xFF;
cidr -= 8;
out += 1;
}
*out = 0;
while (cidr > 0) {
*out |= (uint8_t)(1 << shft);
shft -= 1;
cidr -= 1;
}
}
uint16_t prne_calc_tcp_chksum4 (
const prne_iphdr4_t *ih,
const uint8_t *th,
size_t th_len,
const uint8_t *data,
size_t data_len)
{
uint_fast32_t sum = 0;
// pseudo
sum += prne_recmb_msb16(
ih->saddr[0],
ih->saddr[1]);
sum += prne_recmb_msb16(
ih->saddr[2],
ih->saddr[3]);
sum += prne_recmb_msb16(
ih->daddr[0],
ih->daddr[1]);
sum += prne_recmb_msb16(
ih->daddr[2],
ih->daddr[3]);
sum += ih->protocol;
sum += (uint16_t)(th_len + data_len);
// tcp header
while (th_len > 1) {
sum += prne_recmb_msb16(th[0], th[1]);
th += 2;
th_len -= 2;
}
if (th_len > 0) {
sum += th[0];
}
// data
while (data_len > 1) {
sum += prne_recmb_msb16(data[0], data[1]);
data += 2;
data_len -= 2;
}
if (data_len > 0) {
sum += data[0];
}
return ~((sum & 0xFFFF) + (sum >> 16));
}
uint16_t prne_calc_tcp_chksum6 (
const prne_iphdr6_t *ih,
const uint8_t *th,
size_t th_len,
const uint8_t *data,
size_t data_len)
{
uint_fast32_t sum = 0;
const uint_fast32_t tcp_length = (uint32_t)(th_len + data_len);
// pseudo
sum += prne_recmb_msb16(ih->saddr[0], ih->saddr[1]);
sum += prne_recmb_msb16(ih->saddr[2], ih->saddr[3]);
sum += prne_recmb_msb16(ih->saddr[4], ih->saddr[5]);
sum += prne_recmb_msb16(ih->saddr[6], ih->saddr[7]);
sum += prne_recmb_msb16(ih->saddr[8], ih->saddr[9]);
sum += prne_recmb_msb16(ih->saddr[10], ih->saddr[11]);
sum += prne_recmb_msb16(ih->saddr[12], ih->saddr[13]);
sum += prne_recmb_msb16(ih->saddr[14], ih->saddr[15]);
sum += prne_recmb_msb16(ih->daddr[0], ih->daddr[1]);
sum += prne_recmb_msb16(ih->daddr[2], ih->daddr[3]);
sum += prne_recmb_msb16(ih->daddr[4], ih->daddr[5]);
sum += prne_recmb_msb16(ih->daddr[6], ih->daddr[7]);
sum += prne_recmb_msb16(ih->daddr[8], ih->daddr[9]);
sum += prne_recmb_msb16(ih->daddr[10], ih->daddr[11]);
sum += prne_recmb_msb16(ih->daddr[12], ih->daddr[13]);
sum += prne_recmb_msb16(ih->daddr[14], ih->daddr[15]);
sum += (uint16_t)((tcp_length & 0xFFFF0000) >> 16);
sum += (uint16_t)(tcp_length & 0xFFFF);
sum += ih->next_hdr;
// tcp header
while (th_len > 1) {
sum += prne_recmb_msb16(th[0], th[1]);
th += 2;
th_len -= 2;
}
if (th_len > 0) {
sum += th[0];
}
// data
while (data_len > 1) {
sum += prne_recmb_msb16(data[0], data[1]);
data += 2;
data_len -= 2;
}
if (data_len > 0) {
sum += data[0];
}
return ~((sum & 0xFFFF) + (sum >> 16));
}
void prne_ser_iphdr4 (uint8_t *mem, const prne_iphdr4_t *in) {
mem[0] = (4 << 4) | (in->ihl & 0x0F);
mem[1] = 0;
mem[2] = prne_getmsb16(in->total_len, 0);
mem[3] = prne_getmsb16(in->total_len, 1);
mem[4] = prne_getmsb16(in->id, 0);
mem[5] = prne_getmsb16(in->id, 1);
mem[6] = 0;
mem[7] = 0;
mem[8] = in->ttl;
mem[9] = in->protocol;
mem[10] = 0;
mem[11] = 0;
mem[12] = in->saddr[0];
mem[13] = in->saddr[1];
mem[14] = in->saddr[2];
mem[15] = in->saddr[3];
mem[16] = in->daddr[0];
mem[17] = in->daddr[1];
mem[18] = in->daddr[2];
mem[19] = in->daddr[3];
}
void prne_ser_iphdr6 (uint8_t *mem, const prne_iphdr6_t *in) {
mem[0] = (6 << 4);
mem[1] = prne_getmsb32(in->flow_label, 1) & 0xF;
mem[2] = prne_getmsb32(in->flow_label, 2);
mem[3] = prne_getmsb32(in->flow_label, 3);
mem[4] = prne_getmsb16(in->payload_len, 0);
mem[5] = prne_getmsb16(in->payload_len, 1);
mem[6] = in->next_hdr;
mem[7] = in->hop_limit;
memcpy(mem + 8, in->saddr, 16);
memcpy(mem + 24, in->daddr, 16);
}
void prne_dser_iphdr4 (const uint8_t *data, prne_iphdr4_t *out) {
out->ihl = data[0] & 0x0F;
out->total_len = prne_recmb_msb16(data[2], data[3]);
out->id = prne_recmb_msb16(data[4], data[5]);
out->ttl = data[8];
out->protocol = data[9];
out->saddr[0] = data[12];
out->saddr[1] = data[13];
out->saddr[2] = data[14];
out->saddr[3] = data[15];
out->daddr[0] = data[16];
out->daddr[1] = data[17];
out->daddr[2] = data[18];
out->daddr[3] = data[19];
}
void prne_dser_iphdr6 (const uint8_t *data, prne_iphdr6_t *out) {
out->flow_label = prne_recmb_msb32(0, data[1] & 0x0F, data[2], data[3]);
out->payload_len = prne_recmb_msb16(data[4], data[5]);
out->next_hdr = data[6];
out->hop_limit = data[7];
memcpy(out->saddr, data + 8, 16);
memcpy(out->daddr, data + 24, 16);
}
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