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Merged
MarkusLassila merged 2 commits into from
Mar 12, 2026
Merged

Add TCP Listen and Accept #196

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d50ef6d
app: Add AT#XLISTEN and AT#XACCEPT
MarkusLassila Feb 24, 2026
c10df75
tests: Add unit tests for AT#XLISTEN and AT#XACCEPT
MarkusLassila Mar 12, 2026
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210 changes: 172 additions & 38 deletions app/src/sm_at_socket.c
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Original file line number Diff line number Diff line change
Expand Up @@ -86,9 +86,11 @@ static struct sm_socket {
int family; /* Socket address family */
int fd; /* Socket descriptor. */
uint16_t cid; /* PDP Context ID, 0: primary; 1~10: secondary */
uint16_t local_port; /* Explicitly bound local port. */
int send_flags; /* Send flags */
bool send_cb_set: 1; /* Send callback set */
bool connected: 1; /* Connected flag. */
bool listen: 1; /* Listen flag for TCP server sockets. */
struct sm_async_poll async_poll; /* Async poll info. */
struct sm_send_ntf send_ntf; /* Send notification info. */
struct modem_pipe *pipe; /* AT pipe associated with this socket */
Expand Down Expand Up @@ -117,9 +119,11 @@ static void init_socket(struct sm_socket *socket)
socket->family = NRF_AF_UNSPEC;
socket->fd = INVALID_SOCKET;
socket->cid = 0;
socket->local_port = 0;
socket->send_flags = 0;
socket->send_cb_set = false;
socket->connected = false;
socket->listen = false;
socket->send_ntf = (struct sm_send_ntf){0};
socket->async_poll = (struct sm_async_poll){0};
socket->pipe = sm_at_host_get_current_pipe();
Expand Down Expand Up @@ -233,6 +237,10 @@ static void auto_reception(struct sm_socket *sock)
if (sock == NULL) {
return;
}
if (sock->listen) {
return;
}

if (sock->connected || sock->type == NRF_SOCK_RAW) {
err = do_recv(sock, 0, NRF_MSG_DONTWAIT,
sock->async_poll.adr_hex ? AT_SOCKET_MODE_HEX
Expand Down Expand Up @@ -541,10 +549,6 @@ static int do_socket_open(struct sm_socket *sock)
ret = nrf_socket(sock->family, NRF_SOCK_DGRAM, NRF_IPPROTO_UDP);
proto = NRF_IPPROTO_UDP;
} else if (sock->type == NRF_SOCK_RAW) {
if (sock->role != NRF_SO_SEC_ROLE_CLIENT) {
LOG_ERR("Raw socket: Role must be client");
return -EINVAL;
}
ret = nrf_socket(sock->family, NRF_SOCK_RAW, NRF_IPPROTO_RAW);
proto = NRF_IPPROTO_IP;
} else {
Expand Down Expand Up @@ -649,18 +653,6 @@ static int do_secure_socket_open(struct sm_socket *sock, int peer_verify)
ret = -errno;
goto error;
}
/* Set up (D)TLS server role if applicable */
if (sock->role == AT_SOCKET_ROLE_SERVER) {
int tls_role = NRF_SO_SEC_ROLE_SERVER;

ret = nrf_setsockopt(sock->fd, NRF_SOL_SECURE, NRF_SO_SEC_ROLE, &tls_role,
sizeof(int));
if (ret) {
LOG_ERR("nrf_setsockopt(%d) error: %d", NRF_SO_SEC_ROLE, -errno);
ret = -errno;
goto error;
}
}

rsp_send("\r\n#XSSOCKET: %d,%d,%d\r\n", sock->fd, sock->type, proto);

Expand Down Expand Up @@ -745,6 +737,10 @@ static int at_sockopt_to_sockopt(enum at_sockopt at_option, int *level, int *opt
*level = NRF_SOL_SOCKET;
*option = NRF_SO_RAI;
break;
case AT_SO_TCP_SRV_SESSTIMEO:
*level = NRF_IPPROTO_TCP;
*option = NRF_SO_TCP_SRV_SESSTIMEO;
break;

default:
LOG_WRN("Unsupported option: %d", at_option);
Expand Down Expand Up @@ -922,7 +918,7 @@ static int sec_sockopt_get(struct sm_socket *sock, enum at_sec_sockopt at_option
return ret;
}

int bind_to_local_addr(struct sm_socket *sock, uint16_t port)
static int bind_to_local_addr(struct sm_socket *sock, uint16_t port)
{
int ret;

Expand Down Expand Up @@ -981,6 +977,7 @@ int bind_to_local_addr(struct sm_socket *sock, uint16_t port)
return -EINVAL;
}

sock->local_port = port;
return 0;
}

Expand Down Expand Up @@ -1385,15 +1382,6 @@ STATIC int handle_at_secure_socket(enum at_parser_cmd_type cmd_type,
if (err) {
goto error;
}
/** Peer verification level for TLS connection.
* - 0 - none
* - 1 - optional
* - 2 - required
* If not set, socket will use defaults (none for servers,
* required for clients)
*/
uint16_t peer_verify;

err = at_parser_num_get(parser, 2, &sock->type);
if (err) {
goto error;
Expand All @@ -1402,19 +1390,14 @@ STATIC int handle_at_secure_socket(enum at_parser_cmd_type cmd_type,
if (err) {
goto error;
}
if (sock->role == AT_SOCKET_ROLE_SERVER) {
peer_verify = ZSOCK_TLS_PEER_VERIFY_NONE;
} else if (sock->role == AT_SOCKET_ROLE_CLIENT) {
peer_verify = ZSOCK_TLS_PEER_VERIFY_REQUIRED;
} else {
err = -EINVAL;
goto error;
}
sock->sec_tag = SEC_TAG_TLS_INVALID;
err = at_parser_num_get(parser, 4, &sock->sec_tag);
if (err) {
goto error;
}

uint16_t peer_verify = ZSOCK_TLS_PEER_VERIFY_REQUIRED;

if (param_count > 5) {
err = at_parser_num_get(parser, 5, &peer_verify);
if (err) {
Expand Down Expand Up @@ -1695,10 +1678,6 @@ STATIC int handle_at_connect(enum at_parser_cmd_type cmd_type, struct at_parser
if (sock == NULL) {
return -EINVAL;
}
if (sock->role != AT_SOCKET_ROLE_CLIENT) {
LOG_ERR("Invalid role");
return -EOPNOTSUPP;
}
err = util_string_get(parser, 2, url, &size);
if (err) {
return err;
Expand Down Expand Up @@ -2012,6 +1991,161 @@ STATIC int handle_at_recvfrom(enum at_parser_cmd_type cmd_type, struct at_parser
return err;
}

static int do_listen(struct sm_socket *sock)
{
int ret;

if (sock->type != NRF_SOCK_STREAM || sock->local_port == 0 ||
Comment thread
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sock->sec_tag != SEC_TAG_TLS_INVALID) {
return -EOPNOTSUPP;
}

/* Set the socket to non-blocking mode, so accept() won't block. */
ret = nrf_fcntl(sock->fd, NRF_F_SETFL, NRF_O_NONBLOCK);
if (ret) {
LOG_ERR("nrf_fcntl() failed: %d", -errno);
return -errno;
}

/* nRF modem ignores the backlog parameter. Backlog in modem is fixed to 2. */
ret = nrf_listen(sock->fd, 2);
if (ret) {
LOG_ERR("nrf_listen() failed: %d", -errno);
return -errno;
}

sock->listen = true;
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return 0;
}

SM_AT_CMD_CUSTOM(xlisten, "AT#XLISTEN", handle_at_listen);
STATIC int handle_at_listen(enum at_parser_cmd_type cmd_type, struct at_parser *parser, uint32_t)
{
int err = -EINVAL;
int fd;

struct sm_socket *sock = NULL;

switch (cmd_type) {
case AT_PARSER_CMD_TYPE_SET:
err = at_parser_num_get(parser, 1, &fd);
if (err) {
return err;
}
sock = find_socket(fd);
if (sock == NULL) {
return -EINVAL;
}
err = do_listen(sock);
break;

case AT_PARSER_CMD_TYPE_READ:
for (int i = 0; i < SM_MAX_SOCKET_COUNT; i++) {
if (socks[i].fd != INVALID_SOCKET && socks[i].listen) {
rsp_send("\r\n#XLISTEN: %d,%d,%d\r\n", socks[i].fd, socks[i].cid,
socks[i].local_port);
}
}
err = 0;
break;

case AT_PARSER_CMD_TYPE_TEST:
rsp_send("\r\n#XLISTEN: <handle>\r\n");
err = 0;
break;

default:
break;
}

return err;
}

static int do_accept(struct sm_socket *sock)
{
int ret;
struct net_sockaddr remote;
net_socklen_t addrlen = sizeof(struct net_sockaddr);
char peer_addr[NRF_INET6_ADDRSTRLEN] = {0};
uint16_t peer_port = 0;
struct async_poll_ctx *poll_ctx = poll_ctx_from_sock(sock);

if (sock->type != NRF_SOCK_STREAM || !sock->listen) {
return -EOPNOTSUPP;
}

ret = nrf_accept(sock->fd, (struct nrf_sockaddr *)&remote, (nrf_socklen_t *)&addrlen);
if (ret < 0) {
LOG_ERR("nrf_accept() failed: %d", -errno);
return -errno;
}

struct sm_socket *new_sock = find_avail_socket();
if (new_sock == NULL) {
LOG_ERR("Max socket count reached, closing accepted socket");
nrf_close(ret);
return -EINVAL;
}
init_socket(new_sock);
new_sock->fd = ret;
new_sock->family = remote.sa_family;
new_sock->type = NRF_SOCK_STREAM;
new_sock->role = AT_SOCKET_ROLE_CLIENT;
new_sock->cid = sock->cid;
new_sock->connected = true;

util_get_peer_addr(&remote, peer_addr, &peer_port);
rsp_send("\r\n#XACCEPT: %d,%d,\"%s\",%d\r\n", new_sock->fd, new_sock->cid, peer_addr,
peer_port);

/* Update poll events for xapoll and automatic data reception */
new_sock->async_poll.adr_flags = poll_ctx->adr_flags;
new_sock->async_poll.adr_hex = poll_ctx->adr_hex;
new_sock->async_poll.xapoll_events_requested = poll_ctx->xapoll_events_requested;
update_poll_events(new_sock,
NRF_POLLIN | NRF_POLLOUT | NRF_POLLERR | NRF_POLLHUP | NRF_POLLNVAL,
true);

/* Restore POLLIN for listening socket. */
update_poll_events(sock, NRF_POLLIN, true);

return 0;
}

SM_AT_CMD_CUSTOM(xaccept, "AT#XACCEPT", handle_at_accept);
STATIC int handle_at_accept(enum at_parser_cmd_type cmd_type, struct at_parser *parser, uint32_t)
{
int err = -EINVAL;
int fd;

struct sm_socket *sock = NULL;

switch (cmd_type) {
case AT_PARSER_CMD_TYPE_SET:
err = at_parser_num_get(parser, 1, &fd);
if (err) {
return err;
}
sock = find_socket(fd);
if (sock == NULL) {
return -EINVAL;
}
err = do_accept(sock);
break;

case AT_PARSER_CMD_TYPE_TEST:
rsp_send("\r\n#XACCEPT: <handle>\r\n");
err = 0;
break;

default:
break;
}

return err;
}

SM_AT_CMD_CUSTOM(xgetaddrinfo, "AT#XGETADDRINFO", handle_at_getaddrinfo);
STATIC int handle_at_getaddrinfo(enum at_parser_cmd_type cmd_type, struct at_parser *parser,
uint32_t param_count)
Expand Down
1 change: 1 addition & 0 deletions app/src/sm_sockopt.h
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Original file line number Diff line number Diff line change
Expand Up @@ -24,6 +24,7 @@ enum at_sockopt {
AT_SO_IP_ECHO_REPLY = 31,
AT_SO_IPV6_ECHO_REPLY = 32,
AT_SO_BINDTOPDN = 40,
AT_SO_TCP_SRV_SESSTIMEO = 55,
AT_SO_RAI = 61,
AT_SO_IPV6_DELAYED_ADDR_REFRESH = 62,
};
Expand Down
6 changes: 6 additions & 0 deletions app/tests/at_socket/src/nrf_modem_at_wrapper.c
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Original file line number Diff line number Diff line change
Expand Up @@ -38,6 +38,8 @@ extern int handle_at_recvcfg_wrapper_xrecvcfg(char *buf, size_t len, char *at_cm
extern int handle_at_socketopt_wrapper_xsocketopt(char *buf, size_t len, char *at_cmd);
extern int handle_at_secure_socket_wrapper_xssocket(char *buf, size_t len, char *at_cmd);
extern int handle_at_secure_socketopt_wrapper_xssocketopt(char *buf, size_t len, char *at_cmd);
extern int handle_at_listen_wrapper_xlisten(char *buf, size_t len, char *at_cmd);
extern int handle_at_accept_wrapper_xaccept(char *buf, size_t len, char *at_cmd);

/* Wrapper for nrf_modem_at_cmd that handles custom commands */
int nrf_modem_at_cmd(void *buf, size_t buf_size, const char *fmt, ...)
Expand Down Expand Up @@ -73,6 +75,10 @@ int nrf_modem_at_cmd(void *buf, size_t buf_size, const char *fmt, ...)
ret = handle_at_close_wrapper_xclose((char *)buf, buf_size, at_cmd);
} else if (strncasecmp(at_cmd, "AT#XBIND", 8) == 0) {
ret = handle_at_bind_wrapper_xbind((char *)buf, buf_size, at_cmd);
} else if (strncasecmp(at_cmd, "AT#XLISTEN", 10) == 0) {
ret = handle_at_listen_wrapper_xlisten((char *)buf, buf_size, at_cmd);
} else if (strncasecmp(at_cmd, "AT#XACCEPT", 10) == 0) {
ret = handle_at_accept_wrapper_xaccept((char *)buf, buf_size, at_cmd);
} else if (strncasecmp(at_cmd, "AT#XCONNECT", 11) == 0) {
ret = handle_at_connect_wrapper_xconnect((char *)buf, buf_size, at_cmd);
} else if (strncasecmp(at_cmd, "AT#XSENDTO", 10) == 0) {
Expand Down
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