v4.19.13 snapshot.
diff --git a/arch/um/drivers/net_user.c b/arch/um/drivers/net_user.c
new file mode 100644
index 0000000..e9f8445
--- /dev/null
+++ b/arch/um/drivers/net_user.c
@@ -0,0 +1,271 @@
+/*
+ * Copyright (C) 2001 - 2007 Jeff Dike (jdike@{addtoit,linux.intel}.com)
+ * Licensed under the GPL
+ */
+
+#include <stdio.h>
+#include <unistd.h>
+#include <stdarg.h>
+#include <errno.h>
+#include <stddef.h>
+#include <string.h>
+#include <sys/socket.h>
+#include <sys/wait.h>
+#include <net_user.h>
+#include <os.h>
+#include <um_malloc.h>
+
+int tap_open_common(void *dev, char *gate_addr)
+{
+ int tap_addr[4];
+
+ if (gate_addr == NULL)
+ return 0;
+ if (sscanf(gate_addr, "%d.%d.%d.%d", &tap_addr[0],
+ &tap_addr[1], &tap_addr[2], &tap_addr[3]) != 4) {
+ printk(UM_KERN_ERR "Invalid tap IP address - '%s'\n",
+ gate_addr);
+ return -EINVAL;
+ }
+ return 0;
+}
+
+void tap_check_ips(char *gate_addr, unsigned char *eth_addr)
+{
+ int tap_addr[4];
+
+ if ((gate_addr != NULL) &&
+ (sscanf(gate_addr, "%d.%d.%d.%d", &tap_addr[0],
+ &tap_addr[1], &tap_addr[2], &tap_addr[3]) == 4) &&
+ (eth_addr[0] == tap_addr[0]) &&
+ (eth_addr[1] == tap_addr[1]) &&
+ (eth_addr[2] == tap_addr[2]) &&
+ (eth_addr[3] == tap_addr[3])) {
+ printk(UM_KERN_ERR "The tap IP address and the UML eth IP "
+ "address must be different\n");
+ }
+}
+
+/* Do reliable error handling as this fails frequently enough. */
+void read_output(int fd, char *output, int len)
+{
+ int remain, ret, expected;
+ char c;
+ char *str;
+
+ if (output == NULL) {
+ output = &c;
+ len = sizeof(c);
+ }
+
+ *output = '\0';
+ ret = read(fd, &remain, sizeof(remain));
+
+ if (ret != sizeof(remain)) {
+ if (ret < 0)
+ ret = -errno;
+ expected = sizeof(remain);
+ str = "length";
+ goto err;
+ }
+
+ while (remain != 0) {
+ expected = (remain < len) ? remain : len;
+ ret = read(fd, output, expected);
+ if (ret != expected) {
+ if (ret < 0)
+ ret = -errno;
+ str = "data";
+ goto err;
+ }
+ remain -= ret;
+ }
+
+ return;
+
+err:
+ if (ret < 0)
+ printk(UM_KERN_ERR "read_output - read of %s failed, "
+ "errno = %d\n", str, -ret);
+ else
+ printk(UM_KERN_ERR "read_output - read of %s failed, read only "
+ "%d of %d bytes\n", str, ret, expected);
+}
+
+int net_read(int fd, void *buf, int len)
+{
+ int n;
+
+ n = read(fd, buf, len);
+
+ if ((n < 0) && (errno == EAGAIN))
+ return 0;
+ else if (n == 0)
+ return -ENOTCONN;
+ return n;
+}
+
+int net_recvfrom(int fd, void *buf, int len)
+{
+ int n;
+
+ CATCH_EINTR(n = recvfrom(fd, buf, len, 0, NULL, NULL));
+ if (n < 0) {
+ if (errno == EAGAIN)
+ return 0;
+ return -errno;
+ }
+ else if (n == 0)
+ return -ENOTCONN;
+ return n;
+}
+
+int net_write(int fd, void *buf, int len)
+{
+ int n;
+
+ n = write(fd, buf, len);
+
+ if ((n < 0) && (errno == EAGAIN))
+ return 0;
+ else if (n == 0)
+ return -ENOTCONN;
+ return n;
+}
+
+int net_send(int fd, void *buf, int len)
+{
+ int n;
+
+ CATCH_EINTR(n = send(fd, buf, len, 0));
+ if (n < 0) {
+ if (errno == EAGAIN)
+ return 0;
+ return -errno;
+ }
+ else if (n == 0)
+ return -ENOTCONN;
+ return n;
+}
+
+int net_sendto(int fd, void *buf, int len, void *to, int sock_len)
+{
+ int n;
+
+ CATCH_EINTR(n = sendto(fd, buf, len, 0, (struct sockaddr *) to,
+ sock_len));
+ if (n < 0) {
+ if (errno == EAGAIN)
+ return 0;
+ return -errno;
+ }
+ else if (n == 0)
+ return -ENOTCONN;
+ return n;
+}
+
+struct change_pre_exec_data {
+ int close_me;
+ int stdout_fd;
+};
+
+static void change_pre_exec(void *arg)
+{
+ struct change_pre_exec_data *data = arg;
+
+ close(data->close_me);
+ dup2(data->stdout_fd, 1);
+}
+
+static int change_tramp(char **argv, char *output, int output_len)
+{
+ int pid, fds[2], err;
+ struct change_pre_exec_data pe_data;
+
+ err = os_pipe(fds, 1, 0);
+ if (err < 0) {
+ printk(UM_KERN_ERR "change_tramp - pipe failed, err = %d\n",
+ -err);
+ return err;
+ }
+ pe_data.close_me = fds[0];
+ pe_data.stdout_fd = fds[1];
+ pid = run_helper(change_pre_exec, &pe_data, argv);
+
+ if (pid > 0) /* Avoid hang as we won't get data in failure case. */
+ read_output(fds[0], output, output_len);
+
+ close(fds[0]);
+ close(fds[1]);
+
+ if (pid > 0)
+ helper_wait(pid);
+ return pid;
+}
+
+static void change(char *dev, char *what, unsigned char *addr,
+ unsigned char *netmask)
+{
+ char addr_buf[sizeof("255.255.255.255\0")];
+ char netmask_buf[sizeof("255.255.255.255\0")];
+ char version[sizeof("nnnnn\0")];
+ char *argv[] = { "uml_net", version, what, dev, addr_buf,
+ netmask_buf, NULL };
+ char *output;
+ int output_len, pid;
+
+ sprintf(version, "%d", UML_NET_VERSION);
+ sprintf(addr_buf, "%d.%d.%d.%d", addr[0], addr[1], addr[2], addr[3]);
+ sprintf(netmask_buf, "%d.%d.%d.%d", netmask[0], netmask[1],
+ netmask[2], netmask[3]);
+
+ output_len = UM_KERN_PAGE_SIZE;
+ output = uml_kmalloc(output_len, UM_GFP_KERNEL);
+ if (output == NULL)
+ printk(UM_KERN_ERR "change : failed to allocate output "
+ "buffer\n");
+
+ pid = change_tramp(argv, output, output_len);
+ if (pid < 0) {
+ kfree(output);
+ return;
+ }
+
+ if (output != NULL) {
+ printk("%s", output);
+ kfree(output);
+ }
+}
+
+void open_addr(unsigned char *addr, unsigned char *netmask, void *arg)
+{
+ change(arg, "add", addr, netmask);
+}
+
+void close_addr(unsigned char *addr, unsigned char *netmask, void *arg)
+{
+ change(arg, "del", addr, netmask);
+}
+
+char *split_if_spec(char *str, ...)
+{
+ char **arg, *end, *ret = NULL;
+ va_list ap;
+
+ va_start(ap, str);
+ while ((arg = va_arg(ap, char **)) != NULL) {
+ if (*str == '\0')
+ goto out;
+ end = strchr(str, ',');
+ if (end != str)
+ *arg = str;
+ if (end == NULL)
+ goto out;
+ *end++ = '\0';
+ str = end;
+ }
+ ret = str;
+out:
+ va_end(ap);
+ return ret;
+}