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Rename net_checksum161c to net_checksum16.

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How many characters are summed at a time is an irrelevant
implementation detail.
This commit is contained in:
Nicholas J. Kain 2020-10-27 14:45:15 -04:00
parent 918555219b
commit ff8b910222
2 changed files with 16 additions and 16 deletions
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18
src/dhcp.c
View File

@ -40,7 +40,7 @@
#include "nk/log.h"
#include "nk/io.h"
#include "nk/random.h"
#include "nk/net_checksum.h"
#include "nk/net_checksum16.h"
#include "dhcp.h"
#include "state.h"
@ -133,7 +133,7 @@ static ssize_t send_dhcp_unicast(struct client_state_t cs[static 1],
// Returns 1 if IP checksum is correct, otherwise 0.
static int ip_checksum(struct ip_udp_dhcp_packet packet[static 1])
{
return net_checksum161c(&packet->ip, sizeof packet->ip) == 0;
return net_checksum16(&packet->ip, sizeof packet->ip) == 0;
}
// Returns 1 if UDP checksum is correct, otherwise 0.
@ -146,11 +146,11 @@ static int udp_checksum(struct ip_udp_dhcp_packet packet[static 1])
.tot_len = packet->udp.len,
};
uint16_t udpcs =
net_checksum161c(&packet->udp,
net_checksum16(&packet->udp,
min_size_t(ntohs(packet->udp.len),
sizeof *packet - sizeof(struct iphdr)));
uint16_t hdrcs = net_checksum161c(&ph, sizeof ph);
uint16_t cs = net_checksum161c_add(udpcs, hdrcs);
uint16_t hdrcs = net_checksum16(&ph, sizeof ph);
uint16_t cs = net_checksum16_add(udpcs, hdrcs);
return cs == 0;
}
@ -285,10 +285,10 @@ static ssize_t send_dhcp_raw(struct dhcpmsg payload[static 1])
iudmsg.udp.dest = htons(DHCP_SERVER_PORT);
iudmsg.udp.len = htons(ud_len);
iudmsg.udp.check = 0;
uint16_t udpcs = net_checksum161c(&iudmsg.udp, ud_len);
uint16_t phcs = net_checksum161c(&ph, sizeof ph);
iudmsg.udp.check = net_checksum161c_add(udpcs, phcs);
iudmsg.ip.check = net_checksum161c(&iudmsg.ip, sizeof iudmsg.ip);
uint16_t udpcs = net_checksum16(&iudmsg.udp, ud_len);
uint16_t phcs = net_checksum16(&ph, sizeof ph);
iudmsg.udp.check = net_checksum16_add(udpcs, phcs);
iudmsg.ip.check = net_checksum16(&iudmsg.ip, sizeof iudmsg.ip);
struct sockaddr_ll da = {
.sll_family = AF_PACKET,

14
src/nk/net_checksum.h → src/nk/net_checksum16.h
View File

@ -1,5 +1,5 @@
#ifndef NCMLIB_NET_CHECKSUM_H
#define NCMLIB_NET_CHECKSUM_H
#ifndef NCMLIB_NET_CHECKSUM16_H
#define NCMLIB_NET_CHECKSUM16_H
// RFC 1071 is still a good reference.
@ -9,7 +9,7 @@
// representation, fold the carry bits that have spilled into the upper
// 16-bits of the 32-bit unsigned value back into the 16-bit ones-complement
// binary value.
static inline uint16_t net_checksum161c_foldcarry(uint32_t v)
static inline uint16_t net_checksum16_foldcarry(uint32_t v)
{
v = (v >> 16) + (v & 0xffff);
v += v >> 16;
@ -20,7 +20,7 @@ static inline uint16_t net_checksum161c_foldcarry(uint32_t v)
// the binary value returned, when stored to memory, will match
// the result on big endian; if the numeric value returned
// must match big endian results, then call ntohs() on the result.
static uint16_t net_checksum161c(const void *buf, size_t size)
static uint16_t net_checksum16(const void *buf, size_t size)
{
const char *b = (const char *)buf;
const char *bend = b + size;
@ -37,17 +37,17 @@ static uint16_t net_checksum161c(const void *buf, size_t size)
memcpy(&t, b, 2);
sum += t;
}
return ~net_checksum161c_foldcarry(sum + sumo);
return ~net_checksum16_foldcarry(sum + sumo);
}
// For two sequences of bytes A and B that return checksums CS(A) and CS(B),
// this function will calculate the checksum CS(AB) of the concatenated value
// AB given the checksums of the individual parts CS(A) and CS(B).
static inline uint16_t net_checksum161c_add(uint16_t a, uint16_t b)
static inline uint16_t net_checksum16_add(uint16_t a, uint16_t b)
{
const uint32_t A = a;
const uint32_t B = b;
return ~net_checksum161c_foldcarry((~A & 0xffffu) + (~B & 0xffffu));
return ~net_checksum16_foldcarry((~A & 0xffffu) + (~B & 0xffffu));
}
#endif