kernel: net: Introduce initial socket impl

Introduce initial support for POSIX sockets. This commit currently
implements the AF_UNIX family for IPC.

Signed-off-by: Ian Moffett <ian@osmora.org>

4 files changed, 491 insertions, 0 deletions

diff --git a/sys/include/sys/socket.h b/sys/include/sys/socket.h
new file mode 100644
index 0000000..7175da5
--- /dev/null
+++ b/sys/include/sys/socket.h
@@ -0,0 +1,92 @@
+/*
+ * Copyright (c) 2023-2025 Ian Marco Moffett and the Osmora Team.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright notice,
+ *    this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 3. Neither the name of Hyra nor the names of its
+ *    contributors may be used to endorse or promote products derived from
+ *    this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+ * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
+ * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+ * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+ * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+ * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+ * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+ * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+ * POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#ifndef _SYS_SOCKET_H_
+#define _SYS_SOCKET_H_
+
+#include <sys/socketvar.h>
+#if defined(_KERNEL)
+#include <sys/types.h>
+#include <sys/syscall.h>
+#include <sys/mutex.h>
+#else
+#include <stdint.h>
+#include <stddef.h>
+#endif  /* _KERNEL */
+
+#ifndef _SA_FAMILY_T_DEFINED_
+#define _SA_FAMILY_T_DEFINED_
+typedef uint32_t sa_family_t;
+#endif  /* _SA_FAMILY_T_DEFINED_ */
+
+#ifndef _SOCKLEN_T_DEFINED_
+#define _SOCKLEN_T_DEFINED_
+typedef uint32_t socklen_t;
+#endif  /* !_SOCKLEN_T_DEFINED_ */
+
+/*
+ * Address family defines
+ */
+#define AF_UNSPEC 0
+#define AF_UNIX   1
+#define AF_LOCAL  AF_UNIX
+
+/* Socket types */
+#define SOCK_STREAM 1
+
+struct sockaddr_un {
+    sa_family_t sun_family;
+    char sun_path[108];
+};
+
+struct sockaddr {
+    sa_family_t sa_family;
+    char sa_data[14];
+};
+
+#if defined(_KERNEL)
+
+struct ksocket {
+    int sockfd;
+    union {
+        struct sockaddr sockaddr;
+        struct sockaddr_un un;
+    };
+    struct sockbuf buf;
+    struct mutex *mtx;
+};
+#endif  /* _KERNEL */
+
+int socket(int domain, int type, int protocol);
+int bind(int sockfd, const struct sockaddr *addr, socklen_t len);
+
+ssize_t send(int sockfd, const void *buf, size_t size, int flags);
+ssize_t recv(int sockfd, void *buf, size_t len, int flags);
+
+#endif  /* !_SYS_SOCKET_H_ */
diff --git a/sys/include/sys/socketvar.h b/sys/include/sys/socketvar.h
new file mode 100644
index 0000000..e090a70
--- /dev/null
+++ b/sys/include/sys/socketvar.h
@@ -0,0 +1,53 @@
+/*
+ * Copyright (c) 2023-2025 Ian Marco Moffett and the Osmora Team.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright notice,
+ *    this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 3. Neither the name of Hyra nor the names of its
+ *    contributors may be used to endorse or promote products derived from
+ *    this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+ * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
+ * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+ * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+ * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+ * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+ * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+ * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+ * POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#ifndef _SYS_SOCKETVAR_H_
+#define _SYS_SOCKETVAR_H_
+
+#include <sys/types.h>
+#if defined(_KERNEL)
+#include <net/netbuf.h>
+
+/*
+ * Socket buffer
+ *
+ * @buf: Actual data buffer
+ * @head: Buffer head
+ * @tail: Buffer tail
+ * @watermark: Max length
+ */
+struct sockbuf {
+    struct netbuf buf;
+    size_t head;
+    size_t tail;
+    size_t watermark;
+};
+
+#endif  /* _KERNEL */
+#endif  /* !_SYS_SOCKETVAR_H_ */
diff --git a/sys/include/sys/vnode.h b/sys/include/sys/vnode.h
index 3402b02..ff6f995 100644
--- a/sys/include/sys/vnode.h
+++ b/sys/include/sys/vnode.h
@@ -76,6 +76,7 @@ struct vcache {
 #define VDIR    0x02    /* Directory */
 #define VCHR    0x03    /* Character device */
 #define VBLK    0x04    /* Block device */
+#define VSOCK   0x05    /* Socket */
 
 #define VNOVAL -1
 
diff --git a/sys/kern/kern_socket.c b/sys/kern/kern_socket.c
new file mode 100644
index 0000000..7f58921
--- /dev/null
+++ b/sys/kern/kern_socket.c
@@ -0,0 +1,345 @@
+/*
+ * Copyright (c) 2023-2025 Ian Marco Moffett and the Osmora Team.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright notice,
+ *    this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 3. Neither the name of Hyra nor the names of its
+ *    contributors may be used to endorse or promote products derived from
+ *    this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+ * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
+ * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+ * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+ * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+ * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+ * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+ * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+ * POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#include <sys/socket.h>
+#include <sys/sio.h>
+#include <sys/systm.h>
+#include <sys/errno.h>
+#include <sys/syslog.h>
+#include <sys/filedesc.h>
+#include <sys/vnode.h>
+#include <vm/dynalloc.h>
+#include <string.h>
+
+#define pr_trace(fmt, ...) kprintf("socket: " fmt, ##__VA_ARGS__)
+#define pr_error(...) pr_trace(__VA_ARGS__)
+
+static struct vops socket_vops;
+
+/*
+ * Get a kernel socket structure from a
+ * file descriptor.
+ *
+ * @sockfd: File descriptor to lookup
+ * @res: Result pointer
+ *
+ * Returns zero on success, otherwise a less
+ * than zero errno.
+ */
+static int
+get_ksock(int sockfd, struct ksocket **res)
+{
+    struct ksocket *ksock;
+    struct filedesc *fdesc;
+    struct vnode *vp;
+
+    if (res == NULL) {
+        return -EINVAL;
+    }
+
+    /* Grab the file descriptor */
+    fdesc = fd_get(sockfd);
+    if (fdesc == NULL) {
+        return -EBADF;
+    }
+
+    /* Is this even a socket? */
+    if ((vp = fdesc->vp) == NULL) {
+        return -ENOTSOCK;
+    }
+    if (vp->type != VSOCK) {
+        return -ENOTSOCK;
+    }
+
+    ksock = vp->data;
+    if (__unlikely(ksock == NULL)) {
+        return -EIO;
+    }
+
+    *res = ksock;
+    return 0;
+}
+
+/*
+ * VFS reclaim callback for the socket
+ * layer
+ *
+ * Returns zero on success, otherwise a less
+ * than zero errno.
+ */
+static int
+socket_reclaim(struct vnode *vp)
+{
+    struct ksocket *ksock;
+
+    /* Is this even a socket? */
+    if (vp->type != VSOCK) {
+        return -ENOTSOCK;
+    }
+
+    /* Is there any data attached? */
+    if ((ksock = vp->data) == NULL) {
+        return -EIO;
+    }
+
+    fd_close(ksock->sockfd);
+    mutex_free(ksock->mtx);
+    dynfree(ksock);
+    return 0;
+}
+
+/*
+ * Send data to socket - POSIX send(2) core
+ *
+ * @sockfd: File descriptor that backs this socket
+ * @buf: Buffer containing data to transmit
+ * @size: Size of the buffer
+ * @flags: Optional flags
+ *
+ * Returns zero on success, otherwise a less
+ * than zero errno.
+ */
+ssize_t
+send(int sockfd, const void *buf, size_t size, int flags)
+{
+    struct ksocket *ksock;
+    struct sockbuf *sbuf;
+    struct netbuf *netbuf;
+    size_t tail;
+    int error;
+
+    /* Size cannot be zero */
+    if (size == 0) {
+        return -EINVAL;
+    }
+
+    if ((error = get_ksock(sockfd, &ksock)) < 0) {
+        return error;
+    }
+
+    sbuf = &ksock->buf;
+    netbuf = &sbuf->buf;
+    mutex_acquire(ksock->mtx, 0);
+
+    /* Make sure we dont overflow */
+    if (netbuf->len > sbuf->watermark) {
+        mutex_release(ksock->mtx);
+        return -ENOBUFS;
+    }
+
+    if (netbuf->len == 0) {
+        sbuf->head = 0;
+        sbuf->tail = 0;
+    }
+
+    /* Clamp the size if needed */
+    if ((netbuf->len + size) > sbuf->watermark) {
+        size = sbuf->watermark - netbuf->len;
+    }
+    if (size == 0) {
+        return -ENOBUFS;
+    }
+
+    /* Copy the new data */
+    tail = sbuf->tail;
+    memcpy(&netbuf->data[tail], buf, size);
+
+    sbuf->tail += size;
+    netbuf->len += size;
+    mutex_release(ksock->mtx);
+    return size;
+}
+
+/*
+ * Recv data from socket - POSIX recv(2) core
+ *
+ * @sockfd: File descriptor that backs this socket
+ * @buf: RX buffer
+ * @size: Size of the buffer
+ * @flags: Optional flags
+ *
+ * Returns zero on success, otherwise a less
+ * than zero errno.
+ */
+ssize_t
+recv(int sockfd, void *buf, size_t len, int flags)
+{
+    struct ksocket *ksock;
+    struct sockbuf *sbuf;
+    struct netbuf *netbuf;
+    size_t head;
+    int error;
+
+    /* Length cannot be zero */
+    if (len == 0) {
+        return -EINVAL;
+    }
+
+    if ((error = get_ksock(sockfd, &ksock)) < 0) {
+        return error;
+    }
+
+    sbuf = &ksock->buf;
+    netbuf = &sbuf->buf;
+    mutex_acquire(ksock->mtx, 0);
+
+    /* Is it empty? */
+    if (netbuf->len == 0) {
+        sbuf->head = 0;
+        sbuf->tail = 0;
+        return -EAGAIN;
+    }
+
+    if (len > netbuf->len) {
+        len = netbuf->len;
+    }
+
+    head = sbuf->head;
+    memcpy(buf, &netbuf->data[head], len);
+
+    sbuf->head = (sbuf->head + len) % NETBUF_LEN;
+    mutex_release(ksock->mtx);
+    return len;
+}
+
+/*
+ * POSIX socket(7) core
+ *
+ * @domain: Address family (see AF_*)
+ * @type: Socket type
+ * @protocol: Socket protocol
+ *
+ * Returns zero on success, otherwise a less
+ * than zero errno.
+ */
+int
+socket(int domain, int type, int protocol)
+{
+    struct vnode *vp = NULL;
+    struct ksocket *ksock = NULL;
+    struct filedesc *fdesc = NULL;
+    struct sockbuf *sbuf = NULL;
+    int fd, error = -1;
+
+    if ((error = fd_alloc(&fdesc)) < 0) {
+        return error;
+    }
+
+    fd = fdesc->fdno;
+
+    /* Grab a new socket vnode */
+    if ((error = vfs_alloc_vnode(&vp, VSOCK)) < 0) {
+        fd_close(fd);
+        return error;
+    }
+
+    if (vp == NULL) {
+        error = -ENOBUFS;
+        goto fail;
+    }
+
+    ksock = dynalloc(sizeof(*ksock));
+    if (ksock == NULL) {
+        error = -ENOMEM;
+        goto fail;
+    }
+
+    fdesc->vp = vp;
+    vp->vops = &socket_vops;
+
+    sbuf = &ksock->buf;
+    sbuf->head = 0;
+    sbuf->tail = 0;
+
+    switch (domain) {
+    case AF_UNIX:
+        {
+            struct sockaddr_un *un;
+
+            un = &ksock->un;
+            sbuf->watermark = NETBUF_LEN;
+
+            /*
+             * XXX: We could allow actual paths within the
+             *      file system for sockets.
+             */
+            un->sun_family = domain;
+            un->sun_path[0] = '\0';
+            vp->data = ksock;
+        }
+        return fd;
+    default:
+        error = -EINVAL;
+        break;
+    }
+
+fail:
+    if (ksock != NULL)
+        dynfree(ksock);
+    if (vp != NULL)
+        vfs_release_vnode(vp);
+
+    fd_close(fd);
+    return error;
+}
+
+/*
+ * Bind address to socket - POSIX bind(2) core
+ *
+ * @sockfd: File descriptor
+ * @addr: Address to bind
+ * @len: Sockaddr len
+ *
+ * Returns zero on success, otherwise a less
+ * than zero errno.
+ */
+int
+bind(int sockfd, const struct sockaddr *addr, socklen_t len)
+{
+    struct ksocket *ksock;
+    int error;
+
+    if ((error = get_ksock(sockfd, &ksock)) < 0) {
+        kprintf("error=%d\n", error);
+        return error;
+    }
+
+    /* Create the new mutex lock */
+    ksock->mtx = mutex_new("ksocket");
+    if (ksock->mtx == NULL) {
+        return -ENOMEM;
+    }
+    return 0;
+}
+
+static struct vops socket_vops = {
+    .read = NULL,
+    .write = NULL,
+    .reclaim = socket_reclaim,
+};