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Fix socket local_ip selection with multi_if #8

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Merged
philljj merged 2 commits into from
Nov 19, 2025
Merged

Fix socket local_ip selection with multi_if #8

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14d7e10
Fix socket local_ip selection with multi_if
danielinux Nov 16, 2025
1e2d1cb
Actually assign correct address to socket upon accept
danielinux Nov 16, 2025
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207 changes: 207 additions & 0 deletions src/test/unit/unit.c
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Original file line number Diff line number Diff line change
Expand Up @@ -102,6 +102,56 @@ static void reset_heap(void) {
heap.size = 0;
}

static void setup_stack_with_two_ifaces(struct wolfIP *s, ip4 primary_ip, ip4 secondary_ip)
{
wolfIP_init(s);
mock_link_init(s);
mock_link_init_idx(s, TEST_SECOND_IF, NULL);
wolfIP_ipconfig_set(s, primary_ip, 0xFFFFFF00U, 0);
wolfIP_ipconfig_set_ex(s, TEST_SECOND_IF, secondary_ip, 0xFFFFFF00U, 0);
}

static void inject_tcp_syn(struct wolfIP *s, unsigned int if_idx, ip4 dst_ip, uint16_t dst_port)
{
struct wolfIP_tcp_seg syn;
struct wolfIP_ll_dev *ll = wolfIP_getdev_ex(s, if_idx);
union transport_pseudo_header ph;
static const uint8_t src_mac[6] = {0x10, 0x20, 0x30, 0x40, 0x50, 0x60};

ck_assert_ptr_nonnull(ll);
memset(&syn, 0, sizeof(syn));
memcpy(syn.ip.eth.dst, ll->mac, 6);
memcpy(syn.ip.eth.src, src_mac, 6);
syn.ip.eth.type = ee16(ETH_TYPE_IP);
syn.ip.ver_ihl = 0x45;
syn.ip.ttl = 64;
syn.ip.proto = WI_IPPROTO_TCP;
syn.ip.len = ee16(IP_HEADER_LEN + TCP_HEADER_LEN);
syn.ip.src = ee32(0x0A0000A1U);
syn.ip.dst = ee32(dst_ip);
syn.ip.csum = 0;
iphdr_set_checksum(&syn.ip);

syn.src_port = ee16(40000);
syn.dst_port = ee16(dst_port);
syn.seq = ee32(1);
syn.ack = 0;
syn.hlen = TCP_HEADER_LEN << 2;
syn.flags = 0x02;
syn.win = ee16(65535);
syn.csum = 0;
syn.urg = 0;

memset(&ph, 0, sizeof(ph));
ph.ph.src = syn.ip.src;
ph.ph.dst = syn.ip.dst;
ph.ph.proto = WI_IPPROTO_TCP;
ph.ph.len = ee16(TCP_HEADER_LEN);
syn.csum = ee16(transport_checksum(&ph, &syn.src_port));

tcp_input(s, if_idx, &syn, sizeof(struct wolfIP_eth_frame) + IP_HEADER_LEN + TCP_HEADER_LEN);
}


START_TEST(test_fifo_init)
{
Expand Down Expand Up @@ -934,6 +984,155 @@ START_TEST(test_loopback_dest_not_forwarded)
}
END_TEST

START_TEST(test_tcp_listen_rejects_wrong_interface)
{
struct wolfIP s;
const ip4 primary_ip = 0xC0A80001U;
const ip4 secondary_ip = 0xC0A80101U;
const uint16_t listen_port = 12345;
int listen_fd;
struct wolfIP_sockaddr_in addr;
struct tsocket *listener;

setup_stack_with_two_ifaces(&s, primary_ip, secondary_ip);

listen_fd = wolfIP_sock_socket(&s, AF_INET, IPSTACK_SOCK_STREAM, 0);
ck_assert_int_ge(listen_fd, 0);
listener = &s.tcpsockets[listen_fd & ~MARK_TCP_SOCKET];

memset(&addr, 0, sizeof(addr));
addr.sin_family = AF_INET;
addr.sin_port = ee16(listen_port);
addr.sin_addr.s_addr = ee32(primary_ip);
ck_assert_int_eq(wolfIP_sock_bind(&s, listen_fd, (struct wolfIP_sockaddr *)&addr, sizeof(addr)), 0);
ck_assert_int_eq(wolfIP_sock_listen(&s, listen_fd, 1), 0);

inject_tcp_syn(&s, TEST_SECOND_IF, secondary_ip, listen_port);

ck_assert_int_eq(listener->sock.tcp.state, TCP_LISTEN);
ck_assert_int_eq(listener->events & CB_EVENT_READABLE, 0);
}
END_TEST

START_TEST(test_tcp_listen_accepts_bound_interface)
{
struct wolfIP s;
const ip4 primary_ip = 0xC0A80002U;
const ip4 secondary_ip = 0xC0A80101U;
const uint16_t listen_port = 23456;
int listen_fd;
int client_fd;
struct wolfIP_sockaddr_in addr;
struct tsocket *listener;
struct tsocket *client;

setup_stack_with_two_ifaces(&s, primary_ip, secondary_ip);

listen_fd = wolfIP_sock_socket(&s, AF_INET, IPSTACK_SOCK_STREAM, 0);
ck_assert_int_ge(listen_fd, 0);
listener = &s.tcpsockets[listen_fd & ~MARK_TCP_SOCKET];

memset(&addr, 0, sizeof(addr));
addr.sin_family = AF_INET;
addr.sin_port = ee16(listen_port);
addr.sin_addr.s_addr = ee32(secondary_ip);
ck_assert_int_eq(wolfIP_sock_bind(&s, listen_fd, (struct wolfIP_sockaddr *)&addr, sizeof(addr)), 0);
ck_assert_int_eq(wolfIP_sock_listen(&s, listen_fd, 1), 0);

inject_tcp_syn(&s, TEST_SECOND_IF, secondary_ip, listen_port);

ck_assert_int_eq(listener->sock.tcp.state, TCP_SYN_RCVD);
ck_assert_uint_eq(listener->local_ip, secondary_ip);
ck_assert_uint_eq(listener->if_idx, TEST_SECOND_IF);

client_fd = wolfIP_sock_accept(&s, listen_fd, NULL, NULL);
ck_assert_int_ge(client_fd, 0);
client = &s.tcpsockets[client_fd & ~MARK_TCP_SOCKET];
ck_assert_uint_eq(client->local_ip, secondary_ip);
ck_assert_uint_eq(client->bound_local_ip, secondary_ip);
ck_assert_int_eq(client->sock.tcp.state, TCP_ESTABLISHED);
}
END_TEST

START_TEST(test_tcp_listen_accepts_any_interface)
{
struct wolfIP s;
const ip4 primary_ip = 0xC0A80005U;
const ip4 secondary_ip = 0xC0A80105U;
const uint16_t listen_port = 34567;
int listen_fd;
int client_fd;
struct wolfIP_sockaddr_in addr;
struct tsocket *listener;
struct tsocket *client;

setup_stack_with_two_ifaces(&s, primary_ip, secondary_ip);

listen_fd = wolfIP_sock_socket(&s, AF_INET, IPSTACK_SOCK_STREAM, 0);
ck_assert_int_ge(listen_fd, 0);
listener = &s.tcpsockets[listen_fd & ~MARK_TCP_SOCKET];

memset(&addr, 0, sizeof(addr));
addr.sin_family = AF_INET;
addr.sin_port = ee16(listen_port);
addr.sin_addr.s_addr = ee32(IPADDR_ANY);
ck_assert_int_eq(wolfIP_sock_bind(&s, listen_fd, (struct wolfIP_sockaddr *)&addr, sizeof(addr)), 0);
ck_assert_int_eq(wolfIP_sock_listen(&s, listen_fd, 1), 0);

inject_tcp_syn(&s, TEST_SECOND_IF, secondary_ip, listen_port);

ck_assert_int_eq(listener->sock.tcp.state, TCP_SYN_RCVD);
ck_assert_uint_eq(listener->local_ip, secondary_ip);
ck_assert_uint_eq(listener->if_idx, TEST_SECOND_IF);

client_fd = wolfIP_sock_accept(&s, listen_fd, NULL, NULL);
ck_assert_int_ge(client_fd, 0);
client = &s.tcpsockets[client_fd & ~MARK_TCP_SOCKET];
ck_assert_uint_eq(client->local_ip, secondary_ip);
ck_assert_int_eq(client->sock.tcp.state, TCP_ESTABLISHED);
}
END_TEST

START_TEST(test_sock_connect_selects_local_ip_multi_if)
{
struct wolfIP s;
const ip4 primary_ip = 0xC0A80009U;
const ip4 secondary_ip = 0xC0A80109U;
const ip4 remote_primary = 0xC0A800AAU;
const ip4 remote_secondary = 0xC0A801A1U;
int udp_fd;
int tcp_fd;
struct wolfIP_sockaddr_in dst;
struct tsocket *ts;
int ret;

setup_stack_with_two_ifaces(&s, primary_ip, secondary_ip);

udp_fd = wolfIP_sock_socket(&s, AF_INET, IPSTACK_SOCK_DGRAM, 0);
ck_assert_int_ge(udp_fd, 0);
memset(&dst, 0, sizeof(dst));
dst.sin_family = AF_INET;
dst.sin_port = ee16(5555);
dst.sin_addr.s_addr = ee32(remote_secondary);
ck_assert_int_eq(wolfIP_sock_connect(&s, udp_fd, (struct wolfIP_sockaddr *)&dst, sizeof(dst)), 0);
ts = &s.udpsockets[udp_fd & ~MARK_UDP_SOCKET];
ck_assert_uint_eq(ts->local_ip, secondary_ip);
ck_assert_uint_eq(ts->if_idx, TEST_SECOND_IF);

tcp_fd = wolfIP_sock_socket(&s, AF_INET, IPSTACK_SOCK_STREAM, 0);
ck_assert_int_ge(tcp_fd, 0);
memset(&dst, 0, sizeof(dst));
dst.sin_family = AF_INET;
dst.sin_port = ee16(8080);
dst.sin_addr.s_addr = ee32(remote_primary);
ret = wolfIP_sock_connect(&s, tcp_fd, (struct wolfIP_sockaddr *)&dst, sizeof(dst));
ck_assert_int_eq(ret, -WOLFIP_EAGAIN);
ts = &s.tcpsockets[tcp_fd & ~MARK_TCP_SOCKET];
ck_assert_uint_eq(ts->local_ip, primary_ip);
ck_assert_uint_eq(ts->if_idx, TEST_PRIMARY_IF);
}
END_TEST


// Test for `transport_checksum` calculation
START_TEST(test_transport_checksum) {
Expand Down Expand Up @@ -1136,6 +1335,14 @@ Suite *wolf_suite(void)
suite_add_tcase(s, tc_proto);
tcase_add_test(tc_proto, test_loopback_dest_not_forwarded);
suite_add_tcase(s, tc_proto);
tcase_add_test(tc_proto, test_tcp_listen_rejects_wrong_interface);
suite_add_tcase(s, tc_proto);
tcase_add_test(tc_proto, test_tcp_listen_accepts_bound_interface);
suite_add_tcase(s, tc_proto);
tcase_add_test(tc_proto, test_tcp_listen_accepts_any_interface);
suite_add_tcase(s, tc_proto);
tcase_add_test(tc_proto, test_sock_connect_selects_local_ip_multi_if);
suite_add_tcase(s, tc_proto);

tcase_add_test(tc_utils, test_transport_checksum);
suite_add_tcase(s, tc_proto);
Expand Down
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