From 8b599e8c8d32bdbbfe5a5ca696d4d9cdff5d5350 Mon Sep 17 00:00:00 2001
From: Ian Moffett <ian@osmora.org>
Date: Mon, 28 Jul 2025 03:06:19 -0400
Subject: kernel: net: Add socket syscalls

Introduce the following syscalls:

- SYS_socket
- SYS_bind
- SYS_recv
- SYS_send

Signed-off-by: Ian Moffett <ian@osmora.org>
---
 sys/include/sys/socket.h  |   5 +++
 sys/include/sys/syscall.h |   4 ++
 sys/kern/kern_socket.c    | 102 ++++++++++++++++++++++++++++++++++++++++++++++
 sys/kern/kern_syscall.c   |   5 +++
 4 files changed, 116 insertions(+)

diff --git a/sys/include/sys/socket.h b/sys/include/sys/socket.h
index 7175da5..f01e2bf 100644
--- a/sys/include/sys/socket.h
+++ b/sys/include/sys/socket.h
@@ -81,6 +81,11 @@ struct ksocket {
     struct sockbuf buf;
     struct mutex *mtx;
 };
+
+scret_t sys_socket(struct syscall_args *scargs);
+scret_t sys_bind(struct syscall_args *scargs);
+scret_t sys_recv(struct syscall_args *scargs);
+scret_t sys_send(struct syscall_args *scargs);
 #endif  /* _KERNEL */
 
 int socket(int domain, int type, int protocol);
diff --git a/sys/include/sys/syscall.h b/sys/include/sys/syscall.h
index 02629a9..51a1016 100644
--- a/sys/include/sys/syscall.h
+++ b/sys/include/sys/syscall.h
@@ -59,6 +59,10 @@
 #define SYS_setuid  18
 #define SYS_getuid  19
 #define SYS_waitpid 20
+#define SYS_socket  21
+#define SYS_bind    22
+#define SYS_recv    23
+#define SYS_send    24
 
 #if defined(_KERNEL)
 /* Syscall return value and arg type */
diff --git a/sys/kern/kern_socket.c b/sys/kern/kern_socket.c
index 7f58921..a6cc8d2 100644
--- a/sys/kern/kern_socket.c
+++ b/sys/kern/kern_socket.c
@@ -338,6 +338,108 @@ bind(int sockfd, const struct sockaddr *addr, socklen_t len)
     return 0;
 }
 
+/*
+ * socket(7) syscall
+ *
+ * arg0: domain
+ * arg1: type
+ * arg2: protocol
+ */
+scret_t
+sys_socket(struct syscall_args *scargs)
+{
+    int domain = scargs->arg0;
+    int type = scargs->arg1;
+    int protocol = scargs->arg2;
+
+    return socket(domain, type, protocol);
+}
+
+/*
+ * bind(2) syscall
+ *
+ * arg0: sockfd
+ * arg1: addr
+ * arg2: len
+ */
+scret_t
+sys_bind(struct syscall_args *scargs)
+{
+    const struct sockaddr *u_addr = (void *)scargs->arg1;
+    struct sockaddr addr_copy;
+    int sockfd = scargs->arg0;
+    int len = scargs->arg2;
+    int error;
+
+    error = copyin(u_addr, &addr_copy, sizeof(addr_copy));
+    if (error < 0) {
+        return error;
+    }
+
+    return bind(sockfd, &addr_copy, len);
+}
+
+/*
+ * recv(2) syscall
+ *
+ * arg0: sockfd
+ * arg1: buf
+ * arg2: size
+ * arg3: flags
+ */
+scret_t
+sys_recv(struct syscall_args *scargs)
+{
+    char buf[NETBUF_LEN];
+    void *u_buf = (void *)scargs->arg1;
+    int sockfd = scargs->arg0;
+    size_t len = scargs->arg2;
+    int error, flags = scargs->arg3;
+
+    if (len > sizeof(buf)) {
+        return -ENOBUFS;
+    }
+
+    error = recv(sockfd, buf, len, flags);
+    if (error < 0) {
+        pr_error("sys_recv: recv() fail (fd=%d)\n", sockfd);
+        return error;
+    }
+
+    error = copyout(buf, u_buf, len);
+    return (error == 0) ? len : error;
+}
+
+/*
+ * send(2) syscall
+ *
+ * arg0: sockfd
+ * arg1: buf
+ * arg2: size
+ * arg3: flags
+ */
+scret_t
+sys_send(struct syscall_args *scargs)
+{
+    char buf[NETBUF_LEN];
+    const void *u_buf = (void *)scargs->arg1;
+    int sockfd = scargs->arg0;
+    size_t len = scargs->arg2;
+    int error, flags = scargs->arg3;
+
+    if (len > sizeof(buf)) {
+        return -ENOBUFS;
+    }
+
+    error = copyin(u_buf, buf, len);
+    if (error < 0) {
+        pr_error("sys_send: copyin() failure (fd=%d)\n", sockfd);
+        return error;
+    }
+
+    return send(sockfd, buf, len, flags);
+}
+
 static struct vops socket_vops = {
     .read = NULL,
     .write = NULL,
diff --git a/sys/kern/kern_syscall.c b/sys/kern/kern_syscall.c
index cb7e1d2..dd3de4f 100644
--- a/sys/kern/kern_syscall.c
+++ b/sys/kern/kern_syscall.c
@@ -29,6 +29,7 @@
 
 #include <sys/syscall.h>
 #include <sys/sysctl.h>
+#include <sys/socket.h>
 #include <sys/reboot.h>
 #include <sys/types.h>
 #include <sys/ucred.h>
@@ -60,6 +61,10 @@ scret_t(*g_sctab[])(struct syscall_args *) = {
     sys_setuid,  /* SYS_setuid */
     sys_getuid,  /* SYS_getuid */
     sys_waitpid, /* SYS_waitpid */
+    sys_socket,  /* SYS_socket */
+    sys_bind,    /* SYS_bind */
+    sys_recv,    /* SYS_recv */
+    sys_send,    /* SYS_send */
 };
 
 const size_t MAX_SYSCALLS = NELEM(g_sctab);
-- 
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