os-Linux/drivers/ethertap_user.c

0001 // SPDX-License-Identifier: GPL-2.0
0002 /*
0003  * Copyright (C) 2001 - 2007 Jeff Dike (jdike@{addtoit,linux.intel}.com)
0004  * Copyright (C) 2001 Lennert Buytenhek (buytenh@gnu.org) and
0005  * James Leu (jleu@mindspring.net).
0006  * Copyright (C) 2001 by various other people who didn't put their name here.
0007  */
0008
0009 #include <stdio.h>
0010 #include <unistd.h>
0011 #include <errno.h>
0012 #include <string.h>
0013 #include <sys/socket.h>
0014 #include <sys/wait.h>
0015 #include "etap.h"
0016 #include <os.h>
0017 #include <net_user.h>
0018 #include <um_malloc.h>
0019
0020 #define MAX_PACKET ETH_MAX_PACKET
0021
0022 static int etap_user_init(void *data, void *dev)
0023 {
0024     struct ethertap_data *pri = data;
0025
0026     pri->dev = dev;
0027     return 0;
0028 }
0029
0030 struct addr_change {
0031     enum { ADD_ADDR, DEL_ADDR } what;
0032     unsigned char addr[4];
0033     unsigned char netmask[4];
0034 };
0035
0036 static void etap_change(int op, unsigned char *addr, unsigned char *netmask,
0037             int fd)
0038 {
0039     struct addr_change change;
0040     char *output;
0041     int n;
0042
0043     change.what = op;
0044     memcpy(change.addr, addr, sizeof(change.addr));
0045     memcpy(change.netmask, netmask, sizeof(change.netmask));
0046     CATCH_EINTR(n = write(fd, &change, sizeof(change)));
0047     if (n != sizeof(change)) {
0048         printk(UM_KERN_ERR "etap_change - request failed, err = %d\n",
0049                errno);
0050         return;
0051     }
0052
0053     output = uml_kmalloc(UM_KERN_PAGE_SIZE, UM_GFP_KERNEL);
0054     if (output == NULL)
0055         printk(UM_KERN_ERR "etap_change : Failed to allocate output "
0056                "buffer\n");
0057     read_output(fd, output, UM_KERN_PAGE_SIZE);
0058     if (output != NULL) {
0059         printk("%s", output);
0060         kfree(output);
0061     }
0062 }
0063
0064 static void etap_open_addr(unsigned char *addr, unsigned char *netmask,
0065                void *arg)
0066 {
0067     etap_change(ADD_ADDR, addr, netmask, *((int *) arg));
0068 }
0069
0070 static void etap_close_addr(unsigned char *addr, unsigned char *netmask,
0071                 void *arg)
0072 {
0073     etap_change(DEL_ADDR, addr, netmask, *((int *) arg));
0074 }
0075
0076 struct etap_pre_exec_data {
0077     int control_remote;
0078     int control_me;
0079     int data_me;
0080 };
0081
0082 static void etap_pre_exec(void *arg)
0083 {
0084     struct etap_pre_exec_data *data = arg;
0085
0086     dup2(data->control_remote, 1);
0087     close(data->data_me);
0088     close(data->control_me);
0089 }
0090
0091 static int etap_tramp(char *dev, char *gate, int control_me,
0092               int control_remote, int data_me, int data_remote)
0093 {
0094     struct etap_pre_exec_data pe_data;
0095     int pid, err, n;
0096     char version_buf[sizeof("nnnnn\0")];
0097     char data_fd_buf[sizeof("nnnnnn\0")];
0098     char gate_buf[sizeof("nnn.nnn.nnn.nnn\0")];
0099     char *setup_args[] = { "uml_net", version_buf, "ethertap", dev,
0100                    data_fd_buf, gate_buf, NULL };
0101     char *nosetup_args[] = { "uml_net", version_buf, "ethertap",
0102                  dev, data_fd_buf, NULL };
0103     char **args, c;
0104
0105     sprintf(data_fd_buf, "%d", data_remote);
0106     sprintf(version_buf, "%d", UML_NET_VERSION);
0107     if (gate != NULL) {
0108         strncpy(gate_buf, gate, 15);
0109         args = setup_args;
0110     }
0111     else args = nosetup_args;
0112
0113     err = 0;
0114     pe_data.control_remote = control_remote;
0115     pe_data.control_me = control_me;
0116     pe_data.data_me = data_me;
0117     pid = run_helper(etap_pre_exec, &pe_data, args);
0118
0119     if (pid < 0)
0120         err = pid;
0121     close(data_remote);
0122     close(control_remote);
0123     CATCH_EINTR(n = read(control_me, &c, sizeof(c)));
0124     if (n != sizeof(c)) {
0125         err = -errno;
0126         printk(UM_KERN_ERR "etap_tramp : read of status failed, "
0127                "err = %d\n", -err);
0128         return err;
0129     }
0130     if (c != 1) {
0131         printk(UM_KERN_ERR "etap_tramp : uml_net failed\n");
0132         err = helper_wait(pid);
0133     }
0134     return err;
0135 }
0136
0137 static int etap_open(void *data)
0138 {
0139     struct ethertap_data *pri = data;
0140     char *output;
0141     int data_fds[2], control_fds[2], err, output_len;
0142
0143     err = tap_open_common(pri->dev, pri->gate_addr);
0144     if (err)
0145         return err;
0146
0147     err = socketpair(AF_UNIX, SOCK_DGRAM, 0, data_fds);
0148     if (err) {
0149         err = -errno;
0150         printk(UM_KERN_ERR "etap_open - data socketpair failed - "
0151                "err = %d\n", errno);
0152         return err;
0153     }
0154
0155     err = socketpair(AF_UNIX, SOCK_STREAM, 0, control_fds);
0156     if (err) {
0157         err = -errno;
0158         printk(UM_KERN_ERR "etap_open - control socketpair failed - "
0159                "err = %d\n", errno);
0160         goto out_close_data;
0161     }
0162
0163     err = etap_tramp(pri->dev_name, pri->gate_addr, control_fds[0],
0164              control_fds[1], data_fds[0], data_fds[1]);
0165     output_len = UM_KERN_PAGE_SIZE;
0166     output = uml_kmalloc(output_len, UM_GFP_KERNEL);
0167     read_output(control_fds[0], output, output_len);
0168
0169     if (output == NULL)
0170         printk(UM_KERN_ERR "etap_open : failed to allocate output "
0171                "buffer\n");
0172     else {
0173         printk("%s", output);
0174         kfree(output);
0175     }
0176
0177     if (err < 0) {
0178         printk(UM_KERN_ERR "etap_tramp failed - err = %d\n", -err);
0179         goto out_close_control;
0180     }
0181
0182     pri->data_fd = data_fds[0];
0183     pri->control_fd = control_fds[0];
0184     iter_addresses(pri->dev, etap_open_addr, &pri->control_fd);
0185     return data_fds[0];
0186
0187 out_close_control:
0188     close(control_fds[0]);
0189     close(control_fds[1]);
0190 out_close_data:
0191     close(data_fds[0]);
0192     close(data_fds[1]);
0193     return err;
0194 }
0195
0196 static void etap_close(int fd, void *data)
0197 {
0198     struct ethertap_data *pri = data;
0199
0200     iter_addresses(pri->dev, etap_close_addr, &pri->control_fd);
0201     close(fd);
0202
0203     if (shutdown(pri->data_fd, SHUT_RDWR) < 0)
0204         printk(UM_KERN_ERR "etap_close - shutdown data socket failed, "
0205                "errno = %d\n", errno);
0206
0207     if (shutdown(pri->control_fd, SHUT_RDWR) < 0)
0208         printk(UM_KERN_ERR "etap_close - shutdown control socket "
0209                "failed, errno = %d\n", errno);
0210
0211     close(pri->data_fd);
0212     pri->data_fd = -1;
0213     close(pri->control_fd);
0214     pri->control_fd = -1;
0215 }
0216
0217 static void etap_add_addr(unsigned char *addr, unsigned char *netmask,
0218               void *data)
0219 {
0220     struct ethertap_data *pri = data;
0221
0222     tap_check_ips(pri->gate_addr, addr);
0223     if (pri->control_fd == -1)
0224         return;
0225     etap_open_addr(addr, netmask, &pri->control_fd);
0226 }
0227
0228 static void etap_del_addr(unsigned char *addr, unsigned char *netmask,
0229               void *data)
0230 {
0231     struct ethertap_data *pri = data;
0232
0233     if (pri->control_fd == -1)
0234         return;
0235
0236     etap_close_addr(addr, netmask, &pri->control_fd);
0237 }
0238
0239 const struct net_user_info ethertap_user_info = {
0240     .init       = etap_user_init,
0241     .open       = etap_open,
0242     .close      = etap_close,
0243     .remove     = NULL,
0244     .add_address    = etap_add_addr,
0245     .delete_address = etap_del_addr,
0246     .mtu        = ETH_MAX_PACKET,
0247     .max_packet = ETH_MAX_PACKET + ETH_HEADER_ETHERTAP,
0248 };