net: initial loopback interface support

base/usr/include/kernel/net/netif.h

@@ -10,6 +10,7 @@
 
 int net_add_interface(const char * name, fs_node_t * deviceNode);
 fs_node_t * net_if_lookup(const char * name);
+fs_node_t * net_if_route(uint32_t addr);
 
 typedef struct SockData {
 	fs_node_t _fnode;

kernel/net/ipv4.c

@@ -31,7 +31,6 @@
 #define DEFAULT_TCP_WINDOW_SIZE 65535
 
 static int _debug __attribute__((unused)) = 0;
-extern fs_node_t * net_if_any(void);
 
 static void ip_ntoa(const uint32_t src_addr, char * out) {
 	snprintf(out, 16, "%d.%d.%d.%d",
@@ -225,7 +224,7 @@ static long sock_icmp_send(sock_t * sock, const struct msghdr *msg, int flags) {
 	}
 
 	struct sockaddr_in * name = msg->msg_name;
-	fs_node_t * nic = net_if_any();
+	fs_node_t * nic = net_if_route(name->sin_addr.s_addr);
 	if (!nic) return -ENONET;
 	size_t total_length = sizeof(struct ipv4_packet) + msg->msg_iov[0].iov_len;
 
@@ -470,7 +469,7 @@ static long sock_udp_send(sock_t * sock, const struct msghdr *msg, int flags) {
 	printf("udp: want to send to %s\n", dest);
 
 	/* Routing: We need a device to send this on... */
-	fs_node_t * nic = net_if_any();
+	fs_node_t * nic = net_if_route(name->sin_addr.s_addr);
 	if (!nic) return 0;
 
 	size_t total_length = sizeof(struct ipv4_packet) + msg->msg_iov[0].iov_len + sizeof(struct udp_packet);
@@ -582,7 +581,7 @@ static void sock_tcp_close(sock_t * sock) {
 		spin_unlock(tcp_port_lock);
 
 		size_t total_length = sizeof(struct ipv4_packet) + sizeof(struct tcp_header);
-		fs_node_t * nic = net_if_any();
+		fs_node_t * nic = net_if_route(((struct sockaddr_in*)&sock->dest)->sin_addr.s_addr);
 		if (!nic) return;
 
 		struct ipv4_packet * response = malloc(total_length);
@@ -719,7 +718,7 @@ static long sock_tcp_connect(sock_t * sock, const struct sockaddr *addr, socklen
 
 	memcpy(&sock->dest, addr, addrlen);
 
-	fs_node_t * nic = net_if_any();
+	fs_node_t * nic = net_if_route(dest->sin_addr.s_addr);
 	if (!nic) return -ENONET;
 
 	size_t total_length = sizeof(struct ipv4_packet) + sizeof(struct tcp_header);
@@ -844,7 +843,7 @@ static long sock_tcp_send(sock_t * sock, const struct msghdr *msg, int flags) {
 		size_t size_to_send = size_remaining > 1024 ? 1024 : size_remaining;
 		size_t total_length = sizeof(struct ipv4_packet) + sizeof(struct tcp_header) + size_to_send;
 
-		fs_node_t * nic = net_if_any();
+		fs_node_t * nic = net_if_route(((struct sockaddr_in*)&sock->dest)->sin_addr.s_addr);
 		if (!nic) return -ENONET;
 
 		struct ipv4_packet * response = malloc(total_length);

kernel/net/loop.c

@@ -0,0 +1,122 @@
+/**
+ * @file kernel/net/loop.c
+ * @brief Loopback interface
+ *
+ * @copyright
+ * This file is part of ToaruOS and is released under the terms
+ * of the NCSA / University of Illinois License - see LICENSE.md
+ * Copyright (C) 2021 K. Lange
+ */
+#include <kernel/types.h>
+#include <kernel/string.h>
+#include <kernel/printf.h>
+#include <kernel/vfs.h>
+#include <kernel/spinlock.h>
+#include <kernel/list.h>
+#include <kernel/mod/net.h>
+#include <kernel/net/netif.h>
+#include <kernel/net/eth.h>
+#include <errno.h>
+
+#include <sys/socket.h>
+#include <net/if.h>
+
+struct loop_nic {
+	struct EthernetDevice eth;
+	netif_counters_t counts;
+};
+
+static int ioctl_loop(fs_node_t * node, unsigned long request, void * argp) {
+	struct loop_nic * nic = node->device;
+
+	switch (request) {
+		case SIOCGIFHWADDR:
+			return 1;
+		case SIOCGIFADDR:
+			if (nic->eth.ipv4_addr == 0) return -ENOENT;
+			memcpy(argp, &nic->eth.ipv4_addr, sizeof(nic->eth.ipv4_addr));
+			return 0;
+		case SIOCSIFADDR:
+			memcpy(&nic->eth.ipv4_addr, argp, sizeof(nic->eth.ipv4_addr));
+			return 0;
+		case SIOCGIFNETMASK:
+			if (nic->eth.ipv4_subnet == 0) return -ENOENT;
+			memcpy(argp, &nic->eth.ipv4_subnet, sizeof(nic->eth.ipv4_subnet));
+			return 0;
+		case SIOCSIFNETMASK:
+			memcpy(&nic->eth.ipv4_subnet, argp, sizeof(nic->eth.ipv4_subnet));
+			return 0;
+		case SIOCGIFGATEWAY:
+			if (nic->eth.ipv4_subnet == 0) return -ENOENT;
+			memcpy(argp, &nic->eth.ipv4_gateway, sizeof(nic->eth.ipv4_gateway));
+			return 0;
+		case SIOCSIFGATEWAY:
+			memcpy(&nic->eth.ipv4_gateway, argp, sizeof(nic->eth.ipv4_gateway));
+			net_arp_ask(nic->eth.ipv4_gateway, node);
+			return 0;
+
+		case SIOCGIFADDR6:
+			return -ENOENT;
+		case SIOCSIFADDR6:
+			memcpy(&nic->eth.ipv6_addr, argp, sizeof(nic->eth.ipv6_addr));
+			return 0;
+
+		case SIOCGIFFLAGS: {
+			uint32_t * flags = argp;
+			*flags = IFF_RUNNING;
+			*flags |= IFF_UP;
+			*flags |= IFF_LOOPBACK;
+			return 0;
+		}
+
+		case SIOCGIFMTU: {
+			uint32_t * mtu = argp;
+			*mtu = nic->eth.mtu;
+			return 0;
+		}
+
+		case SIOCGIFCOUNTS: {
+			memcpy(argp, &nic->counts, sizeof(netif_counters_t));
+			return 0;
+		}
+
+		default:
+			return -EINVAL;
+	}
+}
+
+static ssize_t write_loop(fs_node_t *node, off_t offset, size_t size, uint8_t *buffer) {
+	struct loop_nic * nic = node->device;
+	nic->counts.rx_count++;
+	nic->counts.tx_count++;
+	nic->counts.rx_bytes += size;
+	nic->counts.tx_bytes += size;
+
+	net_eth_handle((void*)buffer, node);
+	return size;
+}
+
+static void loop_init(struct loop_nic * nic) {
+	nic->eth.device_node = calloc(sizeof(fs_node_t),1);
+	snprintf(nic->eth.device_node->name, 100, "%s", nic->eth.if_name);
+	nic->eth.device_node->flags = FS_BLOCKDEVICE;
+	nic->eth.device_node->mask  = 0666;
+	nic->eth.device_node->ioctl = ioctl_loop;
+	nic->eth.device_node->write = write_loop;
+	nic->eth.device_node->device = nic;
+	nic->eth.mtu = 65536; /* guess */
+
+	nic->eth.ipv4_addr   = 0x0100007F;
+	nic->eth.ipv4_subnet = 0x000000FF;
+
+	net_add_interface(nic->eth.if_name, nic->eth.device_node);
+}
+
+fs_node_t * loopbook_install(void) {
+	struct loop_nic * nic = calloc(1,sizeof(struct loop_nic));
+	snprintf(nic->eth.if_name, 31, "lo");
+	loop_init(nic);
+	return nic->eth.device_node;
+	return 0;
+}
+

kernel/net/netif.c

@@ -22,10 +22,13 @@
 static hashmap_t * interfaces = NULL;
 extern list_t * net_raw_sockets_list;
 static fs_node_t * _if_first = NULL;
+static fs_node_t * _if_loop = NULL;
 
 extern void ipv4_install(void);
 extern hashmap_t * net_arp_cache;
 
+extern fs_node_t * loopbook_install(void);
+
 void net_install(void) {
 	/* Set up virtual devices */
 	map_vfs_directory("/dev/net");
@@ -33,6 +36,8 @@ void net_install(void) {
 	net_raw_sockets_list = list_create("raw sockets", NULL);
 	net_arp_cache = hashmap_create_int(10);
 	ipv4_install();
+	_if_loop = loopbook_install();
+	_if_first = NULL;
 }
 
 /* kinda temporary for now */
@@ -55,3 +60,9 @@ fs_node_t * net_if_lookup(const char * name) {
 fs_node_t * net_if_any(void) {
 	return _if_first;
 }
+
+fs_node_t * net_if_route(uint32_t addr) {
+	/* First off, let's do stupid stuff. */
+	if (addr == 0x0100007F) return _if_loop;
+	return _if_first;
+}