diff --git a/include/nuttx/net/net.h b/include/nuttx/net/net.h
index 2fcdf612aeb..a319b5d345e 100644
--- a/include/nuttx/net/net.h
+++ b/include/nuttx/net/net.h
@@ -162,7 +162,7 @@ struct sock_intf_s
   CODE int        (*si_poll)(FAR struct socket *psock,
                     FAR struct pollfd *fds, bool setup);
   CODE ssize_t    (*si_sendmsg)(FAR struct socket *psock,
-                    FAR struct msghdr *msg, int flags);
+                    FAR const struct msghdr *msg, int flags);
   CODE ssize_t    (*si_recvmsg)(FAR struct socket *psock,
                     FAR struct msghdr *msg, int flags);
   CODE int        (*si_close)(FAR struct socket *psock);
@@ -880,7 +880,7 @@ int psock_connect(FAR struct socket *psock, FAR const struct sockaddr *addr,
  *
  ****************************************************************************/
 
-ssize_t psock_sendmsg(FAR struct socket *psock, FAR struct msghdr *msg,
+ssize_t psock_sendmsg(FAR struct socket *psock, FAR const struct msghdr *msg,
                       int flags);
 
 /****************************************************************************
diff --git a/include/sys/socket.h b/include/sys/socket.h
index ead113a62ef..3cdb3ce75b8 100644
--- a/include/sys/socket.h
+++ b/include/sys/socket.h
@@ -412,7 +412,7 @@ static inline FAR struct cmsghdr *__cmsg_nxthdr(FAR void *__ctl,
   return __ptr;
 }
 
-static inline FAR struct cmsghdr *cmsg_nxthdr(FAR struct msghdr *__msg,
+static inline FAR struct cmsghdr *cmsg_nxthdr(FAR const struct msghdr *__msg,
                                               FAR struct cmsghdr *__cmsg)
 {
   return __cmsg_nxthdr(__msg->msg_control, __msg->msg_controllen, __cmsg);
@@ -462,7 +462,7 @@ int getpeername(int sockfd, FAR struct sockaddr *addr,
                 FAR socklen_t *addrlen);
 
 ssize_t recvmsg(int sockfd, FAR struct msghdr *msg, int flags);
-ssize_t sendmsg(int sockfd, FAR struct msghdr *msg, int flags);
+ssize_t sendmsg(int sockfd, FAR const struct msghdr *msg, int flags);
 
 #if CONFIG_FORTIFY_SOURCE > 0
 fortify_function(send) ssize_t send(int sockfd, FAR const void *buf,
diff --git a/net/bluetooth/bluetooth.h b/net/bluetooth/bluetooth.h
index c45c4333238..1494b5b80d6 100644
--- a/net/bluetooth/bluetooth.h
+++ b/net/bluetooth/bluetooth.h
@@ -387,8 +387,8 @@ void bluetooth_poll(FAR struct net_driver_s *dev,
  *
  ****************************************************************************/
 
-ssize_t bluetooth_sendmsg(FAR struct socket *psock, FAR struct msghdr *msg,
-                          int flags);
+ssize_t bluetooth_sendmsg(FAR struct socket *psock,
+                          FAR const struct msghdr *msg, int flags);
 
 /****************************************************************************
  * Name: bluetooth_container_initialize
diff --git a/net/bluetooth/bluetooth_sendmsg.c b/net/bluetooth/bluetooth_sendmsg.c
index da4df8cc5b4..8259d590018 100644
--- a/net/bluetooth/bluetooth_sendmsg.c
+++ b/net/bluetooth/bluetooth_sendmsg.c
@@ -549,8 +549,8 @@ static ssize_t bluetooth_send(FAR struct socket *psock, FAR const void *buf,
  *
  ****************************************************************************/
 
-ssize_t bluetooth_sendmsg(FAR struct socket *psock, FAR struct msghdr *msg,
-                          int flags)
+ssize_t bluetooth_sendmsg(FAR struct socket *psock,
+                          FAR const struct msghdr *msg, int flags)
 {
   FAR const void *buf = msg->msg_iov->iov_base;
   size_t len = msg->msg_iov->iov_len;
diff --git a/net/can/can.h b/net/can/can.h
index 3a7a50165d0..5ab14a0e50d 100644
--- a/net/can/can.h
+++ b/net/can/can.h
@@ -354,7 +354,7 @@ int psock_can_cansend(FAR struct socket *psock);
  *
  ****************************************************************************/
 
-ssize_t can_sendmsg(FAR struct socket *psock, FAR struct msghdr *msg,
+ssize_t can_sendmsg(FAR struct socket *psock, FAR const struct msghdr *msg,
                     int flags);
 
 /****************************************************************************
diff --git a/net/can/can_sendmsg.c b/net/can/can_sendmsg.c
index 1f3054618a7..023b653e258 100644
--- a/net/can/can_sendmsg.c
+++ b/net/can/can_sendmsg.c
@@ -166,7 +166,7 @@ end_wait:
  *
  ****************************************************************************/
 
-ssize_t can_sendmsg(FAR struct socket *psock, FAR struct msghdr *msg,
+ssize_t can_sendmsg(FAR struct socket *psock, FAR const struct msghdr *msg,
                     int flags)
 {
   FAR struct net_driver_s *dev;
diff --git a/net/icmp/icmp.h b/net/icmp/icmp.h
index eaf82f7abfb..0d615ac0f46 100644
--- a/net/icmp/icmp.h
+++ b/net/icmp/icmp.h
@@ -315,7 +315,7 @@ void icmp_poll(FAR struct net_driver_s *dev, FAR struct icmp_conn_s *conn);
  ****************************************************************************/
 
 #ifdef CONFIG_NET_ICMP_SOCKET
-ssize_t icmp_sendmsg(FAR struct socket *psock, FAR struct msghdr *msg,
+ssize_t icmp_sendmsg(FAR struct socket *psock, FAR const struct msghdr *msg,
                      int flags);
 #endif
 
diff --git a/net/icmp/icmp_sendmsg.c b/net/icmp/icmp_sendmsg.c
index 0aaeacdf438..14cfd15cecb 100644
--- a/net/icmp/icmp_sendmsg.c
+++ b/net/icmp/icmp_sendmsg.c
@@ -265,7 +265,7 @@ end_wait:
  *
  ****************************************************************************/
 
-ssize_t icmp_sendmsg(FAR struct socket *psock, FAR struct msghdr *msg,
+ssize_t icmp_sendmsg(FAR struct socket *psock, FAR const struct msghdr *msg,
                      int flags)
 {
   FAR const void *buf = msg->msg_iov->iov_base;
diff --git a/net/icmpv6/icmpv6.h b/net/icmpv6/icmpv6.h
index 6c3b6eb6763..ef2f24579e8 100644
--- a/net/icmpv6/icmpv6.h
+++ b/net/icmpv6/icmpv6.h
@@ -663,8 +663,8 @@ int icmpv6_foreach(icmpv6_callback_t callback, FAR void *arg);
  ****************************************************************************/
 
 #ifdef CONFIG_NET_ICMPv6_SOCKET
-ssize_t icmpv6_sendmsg(FAR struct socket *psock, FAR struct msghdr *msg,
-                       int flags);
+ssize_t icmpv6_sendmsg(FAR struct socket *psock,
+                       FAR const struct msghdr *msg, int flags);
 #endif
 
 /****************************************************************************
diff --git a/net/icmpv6/icmpv6_sendmsg.c b/net/icmpv6/icmpv6_sendmsg.c
index 60e678f220f..0250e9ac5a4 100644
--- a/net/icmpv6/icmpv6_sendmsg.c
+++ b/net/icmpv6/icmpv6_sendmsg.c
@@ -262,8 +262,8 @@ end_wait:
  *
  ****************************************************************************/
 
-ssize_t icmpv6_sendmsg(FAR struct socket *psock, FAR struct msghdr *msg,
-                       int flags)
+ssize_t icmpv6_sendmsg(FAR struct socket *psock,
+                       FAR const struct msghdr *msg, int flags)
 {
   FAR const void *buf = msg->msg_iov->iov_base;
   size_t len = msg->msg_iov->iov_len;
diff --git a/net/ieee802154/ieee802154.h b/net/ieee802154/ieee802154.h
index 2864ba7989c..bbb648354a4 100644
--- a/net/ieee802154/ieee802154.h
+++ b/net/ieee802154/ieee802154.h
@@ -401,8 +401,8 @@ void ieee802154_poll(FAR struct net_driver_s *dev,
  *
  ****************************************************************************/
 
-ssize_t ieee802154_sendmsg(FAR struct socket *psock, FAR struct msghdr *msg,
-                           int flags);
+ssize_t ieee802154_sendmsg(FAR struct socket *psock,
+                           FAR const struct msghdr *msg, int flags);
 
 /****************************************************************************
  * Name: ieee802154_container_initialize
diff --git a/net/ieee802154/ieee802154_sendmsg.c b/net/ieee802154/ieee802154_sendmsg.c
index 7da627aea14..c9c83673570 100644
--- a/net/ieee802154/ieee802154_sendmsg.c
+++ b/net/ieee802154/ieee802154_sendmsg.c
@@ -627,8 +627,8 @@ static ssize_t ieee802154_send(FAR struct socket *psock, FAR const void *buf,
  *
  ****************************************************************************/
 
-ssize_t ieee802154_sendmsg(FAR struct socket *psock, FAR struct msghdr *msg,
-                           int flags)
+ssize_t ieee802154_sendmsg(FAR struct socket *psock,
+                           FAR const struct msghdr *msg, int flags)
 {
   FAR const void *buf = msg->msg_iov->iov_base;
   size_t len = msg->msg_iov->iov_len;
diff --git a/net/inet/inet_sockif.c b/net/inet/inet_sockif.c
index 208fa3f2c36..b63df5bc599 100644
--- a/net/inet/inet_sockif.c
+++ b/net/inet/inet_sockif.c
@@ -95,7 +95,7 @@ static ssize_t    inet_sendto(FAR struct socket *psock, FAR const void *buf,
                               FAR const struct sockaddr *to,
                               socklen_t tolen);
 static ssize_t    inet_sendmsg(FAR struct socket *psock,
-                               FAR struct msghdr *msg, int flags);
+                               FAR const struct msghdr *msg, int flags);
 static ssize_t    inet_recvmsg(FAR struct socket *psock,
                                FAR struct msghdr *msg, int flags);
 static int        inet_ioctl(FAR struct socket *psock,
@@ -1867,7 +1867,7 @@ static ssize_t inet_sendto(FAR struct socket *psock, FAR const void *buf,
  ****************************************************************************/
 
 static ssize_t inet_sendmsg(FAR struct socket *psock,
-                            FAR struct msghdr *msg, int flags)
+                            FAR const struct msghdr *msg, int flags)
 {
   FAR void *buf = msg->msg_iov->iov_base;
   size_t len = msg->msg_iov->iov_len;
diff --git a/net/local/local.h b/net/local/local.h
index bdeb14bd4c3..3b79a39f224 100644
--- a/net/local/local.h
+++ b/net/local/local.h
@@ -473,7 +473,7 @@ int local_accept(FAR struct socket *psock, FAR struct sockaddr *addr,
  *
  ****************************************************************************/
 
-ssize_t local_sendmsg(FAR struct socket *psock, FAR struct msghdr *msg,
+ssize_t local_sendmsg(FAR struct socket *psock, FAR const struct msghdr *msg,
                       int flags);
 
 /****************************************************************************
diff --git a/net/local/local_sendmsg.c b/net/local/local_sendmsg.c
index c74a2ec5435..b4a5d25301a 100644
--- a/net/local/local_sendmsg.c
+++ b/net/local/local_sendmsg.c
@@ -71,7 +71,7 @@ static void local_freectl(FAR struct local_conn_s *conn, int count)
 }
 
 static int local_sendctl(FAR struct local_conn_s *conn,
-                         FAR struct msghdr *msg)
+                         FAR const struct msghdr *msg)
 {
   FAR struct local_conn_s *peer;
   FAR struct file *filep;
@@ -410,7 +410,7 @@ errout_with_lock:
  *
  ****************************************************************************/
 
-ssize_t local_sendmsg(FAR struct socket *psock, FAR struct msghdr *msg,
+ssize_t local_sendmsg(FAR struct socket *psock, FAR const struct msghdr *msg,
                       int flags)
 {
   FAR const struct sockaddr *to = msg->msg_name;
diff --git a/net/netlink/netlink_sockif.c b/net/netlink/netlink_sockif.c
index 1366914a021..eb17bc19191 100644
--- a/net/netlink/netlink_sockif.c
+++ b/net/netlink/netlink_sockif.c
@@ -67,7 +67,7 @@ static int  netlink_connect(FAR struct socket *psock,
 static int  netlink_poll(FAR struct socket *psock, FAR struct pollfd *fds,
                          bool setup);
 static ssize_t netlink_sendmsg(FAR struct socket *psock,
-                               FAR struct msghdr *msg, int flags);
+                               FAR const struct msghdr *msg, int flags);
 static ssize_t netlink_recvmsg(FAR struct socket *psock,
                                FAR struct msghdr *msg, int flags);
 static int netlink_close(FAR struct socket *psock);
@@ -575,7 +575,7 @@ static int netlink_poll(FAR struct socket *psock, FAR struct pollfd *fds,
  ****************************************************************************/
 
 static ssize_t netlink_sendmsg(FAR struct socket *psock,
-                               FAR struct msghdr *msg, int flags)
+                               FAR const struct msghdr *msg, int flags)
 {
   FAR const void *buf = msg->msg_iov->iov_base;
   FAR const struct sockaddr *to = msg->msg_name;
diff --git a/net/pkt/pkt.h b/net/pkt/pkt.h
index 3753d110093..63d946dafa2 100644
--- a/net/pkt/pkt.h
+++ b/net/pkt/pkt.h
@@ -397,7 +397,7 @@ int pkt_pollteardown(FAR struct socket *psock, FAR struct pollfd *fds);
  *
  ****************************************************************************/
 
-ssize_t pkt_sendmsg(FAR struct socket *psock, FAR struct msghdr *msg,
+ssize_t pkt_sendmsg(FAR struct socket *psock, FAR const struct msghdr *msg,
                     int flags);
 
 #ifdef CONFIG_NET_PKTPROTO_OPTIONS
diff --git a/net/pkt/pkt_sendmsg_unbuffered.c b/net/pkt/pkt_sendmsg_unbuffered.c
index 039a4a99410..b6ddfa56acc 100644
--- a/net/pkt/pkt_sendmsg_unbuffered.c
+++ b/net/pkt/pkt_sendmsg_unbuffered.c
@@ -180,7 +180,7 @@ end_wait:
  *
  ****************************************************************************/
 
-ssize_t pkt_sendmsg(FAR struct socket *psock, FAR struct msghdr *msg,
+ssize_t pkt_sendmsg(FAR struct socket *psock, FAR const struct msghdr *msg,
                     int flags)
 {
   FAR const void *buf = msg->msg_iov->iov_base;
diff --git a/net/rpmsg/rpmsg_sockif.c b/net/rpmsg/rpmsg_sockif.c
index 502053921be..0386ffc5408 100644
--- a/net/rpmsg/rpmsg_sockif.c
+++ b/net/rpmsg/rpmsg_sockif.c
@@ -171,7 +171,8 @@ static int        rpmsg_socket_accept(FAR struct socket *psock,
 static int        rpmsg_socket_poll(FAR struct socket *psock,
                                     FAR struct pollfd *fds, bool setup);
 static ssize_t    rpmsg_socket_sendmsg(FAR struct socket *psock,
-                                       FAR struct msghdr *msg, int flags);
+                                       FAR const struct msghdr *msg,
+                                       int flags);
 static ssize_t    rpmsg_socket_recvmsg(FAR struct socket *psock,
                                        FAR struct msghdr *msg, int flags);
 static int        rpmsg_socket_close(FAR struct socket *psock);
@@ -1182,7 +1183,7 @@ static ssize_t rpmsg_socket_send_single(FAR struct socket *psock,
 }
 
 static ssize_t rpmsg_socket_sendmsg(FAR struct socket *psock,
-                                    FAR struct msghdr *msg, int flags)
+                                    FAR const struct msghdr *msg, int flags)
 {
   FAR struct rpmsg_socket_conn_s *conn = psock->s_conn;
   FAR const struct iovec *buf = msg->msg_iov;
diff --git a/net/socket/sendmsg.c b/net/socket/sendmsg.c
index 7cf4b23c8aa..b20f9409327 100644
--- a/net/socket/sendmsg.c
+++ b/net/socket/sendmsg.c
@@ -69,7 +69,7 @@
  *
  ****************************************************************************/
 
-ssize_t psock_sendmsg(FAR struct socket *psock, FAR struct msghdr *msg,
+ssize_t psock_sendmsg(FAR struct socket *psock, FAR const struct msghdr *msg,
                        int flags)
 {
   /* Verify that non-NULL pointers were passed */
@@ -140,7 +140,7 @@ ssize_t psock_sendmsg(FAR struct socket *psock, FAR struct msghdr *msg,
  *
  ****************************************************************************/
 
-ssize_t sendmsg(int sockfd, FAR struct msghdr *msg, int flags)
+ssize_t sendmsg(int sockfd, FAR const struct msghdr *msg, int flags)
 {
   FAR struct socket *psock;
   FAR struct file *filep;
diff --git a/net/usrsock/usrsock.h b/net/usrsock/usrsock.h
index 9f9e05f78a8..e7f2e8e09ff 100644
--- a/net/usrsock/usrsock.h
+++ b/net/usrsock/usrsock.h
@@ -495,8 +495,8 @@ int usrsock_poll(FAR struct socket *psock, FAR struct pollfd *fds,
  *
  ****************************************************************************/
 
-ssize_t usrsock_sendmsg(FAR struct socket *psock, FAR struct msghdr *msg,
-                        int flags);
+ssize_t usrsock_sendmsg(FAR struct socket *psock,
+                        FAR const struct msghdr *msg, int flags);
 
 /****************************************************************************
  * Name: usrsock_recvmsg
diff --git a/net/usrsock/usrsock_sendmsg.c b/net/usrsock/usrsock_sendmsg.c
index 084806c9318..dfa8f9dc4ea 100644
--- a/net/usrsock/usrsock_sendmsg.c
+++ b/net/usrsock/usrsock_sendmsg.c
@@ -136,18 +136,19 @@ static uint32_t sendto_event(FAR struct net_driver_s *dev,
  ****************************************************************************/
 
 static int do_sendto_request(FAR struct usrsock_conn_s *conn,
-                             FAR struct msghdr *msg, int flags)
+                             FAR const struct msghdr *msg, int flags)
 {
   struct usrsock_request_sendto_s req =
   {
   };
 
   struct iovec bufs[2 + msg->msg_iovlen];
+  socklen_t msg_namelen = msg->msg_namelen;
   int i;
 
-  if (msg->msg_namelen > UINT16_MAX)
+  if (msg_namelen > UINT16_MAX)
     {
-      msg->msg_namelen = UINT16_MAX;
+      msg_namelen = UINT16_MAX;
     }
 
   /* Prepare request for daemon to read. */
@@ -155,7 +156,7 @@ static int do_sendto_request(FAR struct usrsock_conn_s *conn,
   req.head.reqid = USRSOCK_REQUEST_SENDTO;
   req.usockid = conn->usockid;
   req.flags = flags;
-  req.addrlen = msg->msg_namelen;
+  req.addrlen = msg_namelen;
 
   for (i = 0; i < msg->msg_iovlen; i++)
     {
@@ -170,7 +171,7 @@ static int do_sendto_request(FAR struct usrsock_conn_s *conn,
   bufs[0].iov_base = (FAR void *)&req;
   bufs[0].iov_len  = sizeof(req);
   bufs[1].iov_base = msg->msg_name;
-  bufs[1].iov_len  = msg->msg_namelen;
+  bufs[1].iov_len  = msg_namelen;
 
   memcpy(&bufs[2], msg->msg_iov, sizeof(struct iovec) * msg->msg_iovlen);
 
@@ -202,7 +203,7 @@ static int do_sendto_request(FAR struct usrsock_conn_s *conn,
  ****************************************************************************/
 
 ssize_t usrsock_sendmsg(FAR struct socket *psock,
-                        FAR struct msghdr *msg, int flags)
+                        FAR const struct msghdr *msg, int flags)
 {
   FAR struct usrsock_conn_s *conn = psock->s_conn;
   struct usrsock_reqstate_s state =
diff --git a/syscall/syscall.csv b/syscall/syscall.csv
index 3fe9675905d..f4a403fafec 100644
--- a/syscall/syscall.csv
+++ b/syscall/syscall.csv
@@ -155,7 +155,7 @@
 "select","sys/select.h","","int","int","FAR fd_set *","FAR fd_set *","FAR fd_set *","FAR struct timeval *"
 "send","sys/socket.h","defined(CONFIG_NET)","ssize_t","int","FAR const void *","size_t","int"
 "sendfile","sys/sendfile.h","","ssize_t","int","int","FAR off_t *","size_t"
-"sendmsg","sys/socket.h","defined(CONFIG_NET)","ssize_t","int","FAR struct msghdr *","int"
+"sendmsg","sys/socket.h","defined(CONFIG_NET)","ssize_t","int","FAR const struct msghdr *","int"
 "sendto","sys/socket.h","defined(CONFIG_NET)","ssize_t","int","FAR const void *","size_t","int","FAR const struct sockaddr *","socklen_t"
 "setegid","unistd.h","defined(CONFIG_SCHED_USER_IDENTITY)","int","gid_t"
 "setenv","stdlib.h","!defined(CONFIG_DISABLE_ENVIRON)","int","FAR const char *","FAR const char *","int"