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feat: rework icmp_parse_ip_header

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Extend icmp_parse_ip_header to allow optional extraction of destination
IP address and protocol from the IP header
This commit is contained in:
lohhiiccc 2026-02-01 01:47:02 +01:00
parent 84490efc8e
commit ace00ea0f2
4 changed files with 92 additions and 8 deletions
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3
includes/internal/icmp_packet_internal.h
View file

@ -11,7 +11,8 @@ int icmp_build_packet(void *buffer, size_t buffer_len, uint8_t type,
int icmp_parse_ip_header(const void *buffer, size_t buffer_len,
uint8_t *ttl, struct in_addr *src_addr,
size_t *ip_hdr_len);
size_t *ip_hdr_len, struct in_addr *dst_addr,
uint8_t *protocol);
int icmp_parse_icmp_payload(const void *buffer, size_t buffer_len,
size_t ip_hdr_len, uint8_t *type, uint8_t *code,

7
src/packet/parse_ip.c
View file

@ -15,7 +15,8 @@ static size_t extract_ip_header_length(uint8_t version_ihl);
int
icmp_parse_ip_header(const void *buffer, size_t buffer_len, uint8_t *ttl,
struct in_addr *src_addr, size_t *ip_hdr_len)
struct in_addr *src_addr, size_t *ip_hdr_len,
struct in_addr *dst_addr, uint8_t *protocol)
{
if (buffer_len < MIN_IP_HEADER_SIZE)
return -1;
@ -30,6 +31,10 @@ icmp_parse_ip_header(const void *buffer, size_t buffer_len, uint8_t *ttl,
*ttl = h->ttl;
if (src_addr)
src_addr->s_addr = h->saddr;
if (dst_addr)
dst_addr->s_addr = h->daddr;
if (protocol)
*protocol = h->protocol;
if (ip_hdr_len)
*ip_hdr_len = ihl_bytes;

2
src/recv/core/parse_packet.c
View file

@ -9,7 +9,7 @@ recv_parse_packet(const void *buffer, size_t buffer_len,
size_t *ip_hdr_len)
{
if (icmp_parse_ip_header(buffer, buffer_len, ttl, src_addr,
ip_hdr_len) < 0)
ip_hdr_len, NULL, NULL) < 0)
return -1;
if (icmp_parse_icmp_payload(buffer, buffer_len, *ip_hdr_len,

88
tests/packet/test_parse_ip.c
View file

@ -17,7 +17,7 @@ Test(packet_parse_ip, valid_header)
size_t ip_hdr_len = 0;
int ret = icmp_parse_ip_header(buffer, sizeof(buffer), &ttl, &src_addr,
&ip_hdr_len);
&ip_hdr_len, NULL, NULL);
cr_assert_eq(ret, 0, "Should return 0 for valid IP header");
cr_assert_eq(ttl, 64, "TTL should be 64");
@ -39,7 +39,7 @@ Test(packet_parse_ip, extract_ttl)
size_t ip_hdr_len = 0;
int ret = icmp_parse_ip_header(buffer, sizeof(buffer), &ttl, &src_addr,
&ip_hdr_len);
&ip_hdr_len, NULL, NULL);
cr_assert_eq(ret, 0, "Should return 0 for valid header");
cr_assert_eq(ttl, 128, "TTL should be 128");
@ -58,7 +58,7 @@ Test(packet_parse_ip, extract_source_addr)
size_t ip_hdr_len = 0;
int ret = icmp_parse_ip_header(buffer, sizeof(buffer), &ttl, &src_addr,
&ip_hdr_len);
&ip_hdr_len, NULL, NULL);
cr_assert_eq(ret, 0, "Should return 0 for valid header");
cr_assert_eq(src_addr.s_addr, inet_addr("8.8.8.8"),
@ -73,7 +73,7 @@ Test(packet_parse_ip, buffer_too_small)
size_t ip_hdr_len = 0;
int ret = icmp_parse_ip_header(buffer, sizeof(buffer), &ttl, &src_addr,
&ip_hdr_len);
&ip_hdr_len, NULL, NULL);
cr_assert_eq(ret, -1, "Should return -1 when buffer is too small");
}
@ -91,6 +91,84 @@ Test(packet_parse_ip, invalid_version)
size_t ip_hdr_len = 0;
int ret = icmp_parse_ip_header(buffer, sizeof(buffer), &ttl, &src_addr,
&ip_hdr_len);
&ip_hdr_len, NULL, NULL);
cr_assert_eq(ret, -1, "Should return -1 for invalid IP version");
}
Test(packet_parse_ip, extract_dest_addr)
{
uint8_t buffer[20] = {0};
struct ip_header *hdr = (struct ip_header*)buffer;
hdr->version_ihl = 0x45;
hdr->ttl = 64;
hdr->saddr = inet_addr("192.168.1.1");
hdr->daddr = inet_addr("8.8.8.8");
struct in_addr dst_addr = {0};
int ret = icmp_parse_ip_header(buffer, sizeof(buffer), NULL, NULL,
NULL, &dst_addr, NULL);
cr_assert_eq(ret, 0, "Should return 0 for valid header");
cr_assert_eq(dst_addr.s_addr, inet_addr("8.8.8.8"),
"Destination address should match 8.8.8.8");
}
Test(packet_parse_ip, extract_protocol)
{
uint8_t buffer[20] = {0};
struct ip_header *hdr = (struct ip_header*)buffer;
hdr->version_ihl = 0x45;
hdr->ttl = 64;
hdr->protocol = 1; // ICMP
uint8_t protocol = 0;
int ret = icmp_parse_ip_header(buffer, sizeof(buffer), NULL, NULL,
NULL, NULL, &protocol);
cr_assert_eq(ret, 0, "Should return 0 for valid header");
cr_assert_eq(protocol, 1, "Protocol should be 1 (ICMP)");
}
Test(packet_parse_ip, extract_all_fields)
{
uint8_t buffer[20] = {0};
struct ip_header *hdr = (struct ip_header*)buffer;
hdr->version_ihl = 0x45;
hdr->ttl = 128;
hdr->saddr = inet_addr("10.0.0.1");
hdr->daddr = inet_addr("10.0.0.2");
hdr->protocol = 6; // TCP
uint8_t ttl = 0;
struct in_addr src_addr = {0};
struct in_addr dst_addr = {0};
uint8_t protocol = 0;
size_t ip_hdr_len = 0;
int ret = icmp_parse_ip_header(buffer, sizeof(buffer), &ttl, &src_addr,
&ip_hdr_len, &dst_addr, &protocol);
cr_assert_eq(ret, 0, "Should return 0 for valid header");
cr_assert_eq(ttl, 128, "TTL should be 128");
cr_assert_eq(src_addr.s_addr, inet_addr("10.0.0.1"),
"Source address should match");
cr_assert_eq(dst_addr.s_addr, inet_addr("10.0.0.2"),
"Destination address should match");
cr_assert_eq(protocol, 6, "Protocol should be 6 (TCP)");
cr_assert_eq(ip_hdr_len, 20, "Header length should be 20");
}
Test(packet_parse_ip, null_parameters_allowed)
{
uint8_t buffer[20] = {0};
struct ip_header *hdr = (struct ip_header*)buffer;
hdr->version_ihl = 0x45;
hdr->ttl = 64;
int ret = icmp_parse_ip_header(buffer, sizeof(buffer), NULL, NULL,
NULL, NULL, NULL);
cr_assert_eq(ret, 0, "Should return 0 even with all NULL parameters");
}