如何从C程序获取NIC详细信息? [英] How to get NIC details from a C program?
问题描述
我想获取连接到计算机的所有NIC的以下详细信息:
I want to get the following details for all the NICs attached to my computer:
1)接口名称(例如eth0)
1) Interface name (eg. eth0)
2)接口号(例如在 Windows 中)在Linux中
2) Interface Number (like in Windows) if such a thing exists in Linux
3)NIC带宽容量和模式(例如1Gb/s全双工)
3) NIC bandwidth capacity and mode (eg. 1Gb/s full duplex)
推荐答案
You can use getifaddrs()/freeifaddrs() to obtain a linked list of all interfaces, then ioctl(fd, SIOCGIFINDEX, struct ifreq *) to obtain the interface index for each. Since the interfaces are consecutive and always listed (regardless of whether or they are up (active) or not), I choose to enumerate them with a loop using ioctl(fd, SIOCGIFNAME, struct ifreq *) instead. In all cases fd is an AF_INET socket.
要获取接口的双工和速度，您需要使用ioctl(fd, SIOCETHTOOL, struct ifreq *)，将ifr_data指向具有cmd = ETHTOOL_GSET的struct ethtool_cmd.
To obtain the duplex and speed of the interface, you need to use the ioctl(fd, SIOCETHTOOL, struct ifreq *) with the ifr_data pointing to a struct ethtool_cmd having cmd = ETHTOOL_GSET.
如果ioctl失败，则应返回-1，如果成功，则应返回非负值(我相信是零).
The ioctls should return -1 if they fail, and a nonnegative value (zero, I believe) if success.
这是一个示例程序:
#include <unistd.h>
#include <sys/socket.h>
#include <sys/ioctl.h>
#include <netinet/ip.h>
#include <net/if.h>
#include <linux/ethtool.h>
#include <linux/sockios.h>
#include <string.h>
#include <errno.h>
#include <stdio.h>
struct interface {
int index;
int flags; /* IFF_UP etc. */
long speed; /* Mbps; -1 is unknown */
int duplex; /* DUPLEX_FULL, DUPLEX_HALF, or unknown */
char name[IF_NAMESIZE + 1];
};
static int get_interface_common(const int fd, struct ifreq *const ifr, struct interface *const info)
{
struct ethtool_cmd cmd;
int result;
/* Interface flags. */
if (ioctl(fd, SIOCGIFFLAGS, ifr) == -1)
info->flags = 0;
else
info->flags = ifr->ifr_flags;
ifr->ifr_data = (void *)&cmd;
cmd.cmd = ETHTOOL_GSET; /* "Get settings" */
if (ioctl(fd, SIOCETHTOOL, ifr) == -1) {
/* Unknown */
info->speed = -1L;
info->duplex = DUPLEX_UNKNOWN;
} else {
info->speed = ethtool_cmd_speed(&cmd);
info->duplex = cmd.duplex;
}
do {
result = close(fd);
} while (result == -1 && errno == EINTR);
if (result == -1)
return errno;
return 0;
}
int get_interface_by_index(const int index, struct interface *const info)
{
int socketfd, result;
struct ifreq ifr;
if (index < 1 || !info)
return errno = EINVAL;
socketfd = socket(AF_INET, SOCK_DGRAM, IPPROTO_IP);
if (socketfd == -1)
return errno;
ifr.ifr_ifindex = index;
if (ioctl(socketfd, SIOCGIFNAME, &ifr) == -1) {
do {
result = close(socketfd);
} while (result == -1 && errno == EINTR);
return errno = ENOENT;
}
info->index = index;
strncpy(info->name, ifr.ifr_name, IF_NAMESIZE);
info->name[IF_NAMESIZE] = '\0';
return get_interface_common(socketfd, &ifr, info);
}
int get_interface_by_name(const char *const name, struct interface *const info)
{
int socketfd, result;
struct ifreq ifr;
if (!name || !*name || !info)
return errno = EINVAL;
socketfd = socket(AF_INET, SOCK_DGRAM, IPPROTO_IP);
if (socketfd == -1)
return errno;
strncpy(ifr.ifr_name, name, IF_NAMESIZE);
if (ioctl(socketfd, SIOCGIFINDEX, &ifr) == -1) {
do {
result = close(socketfd);
} while (result == -1 && errno == EINTR);
return errno = ENOENT;
}
info->index = ifr.ifr_ifindex;
strncpy(info->name, name, IF_NAMESIZE);
info->name[IF_NAMESIZE] = '\0';
return get_interface_common(socketfd, &ifr, info);
}
int main(int argc, char *argv[])
{
struct interface iface;
int arg;
int status = 0;
if (argc > 1 && (!strcmp(argv[1], "-h") || !strcmp(argv[1], "--help"))) {
fprintf(stderr, "\n");
fprintf(stderr, "Usage: %s { -h | --help }\n", argv[0]);
fprintf(stderr, " %s\n", argv[0]);
fprintf(stderr, " %s INTERFACE ...\n", argv[0]);
fprintf(stderr, "\n");
return 1;
}
if (argc > 1) {
for (arg = 1; arg < argc; arg++) {
if (get_interface_by_name(argv[arg], &iface) != 0) {
fprintf(stderr, "%s: No such interface.\n", argv[arg]);
status = 1;
continue;
}
printf("%s: Interface %d", iface.name, iface.index);
if (iface.flags & IFF_UP)
printf(", up");
if (iface.duplex == DUPLEX_FULL)
printf(", full duplex");
else
if (iface.duplex == DUPLEX_HALF)
printf(", half duplex");
if (iface.speed > 0)
printf(", %ld Mbps", iface.speed);
printf("\n");
}
} else {
for (arg = 1; ; arg++) {
if (get_interface_by_index(arg, &iface) != 0)
break;
printf("%s: Interface %d", iface.name, iface.index);
if (iface.flags & IFF_UP)
printf(", up");
if (iface.duplex == DUPLEX_FULL)
printf(", full duplex");
else
if (iface.duplex == DUPLEX_HALF)
printf(", half duplex");
if (iface.speed > 0)
printf(", %ld Mbps", iface.speed);
printf("\n");
}
}
return status;
}
如果将以上内容另存为iflist.c，则可以使用
If you save the above as iflist.c, you can compile it using
gcc -W -Wall -O3 iflist.c -o iflist
要查看用法，请运行iflist -h.要列出所有接口，请在不带参数的情况下运行它:
To see the usage, run iflist -h. To list all interfaces, run it without parameters:
./iflist
以上将使用我描述的枚举方法.要仅列出特定的接口，请运行它以命名接口:
The above will use the enumeration method I described. To list only specific interfaces, run it naming the interfaces:
./iflist eth0 lo
当然，仅列出了以太网接口的双工和速度.
Duplex and speed is only listed for ethernet interfaces, of course.
编辑后添加:
如果以上程序未提供接口的带宽和模式，则此版本为简化版本，可报告确切原因(错误).这个以接口名称作为命令行参数.它不枚举接口.
If the above program does not supply the bandwidth and mode for an interface, here is a simplified version which reports the exact reason (errors). This one takes the interface names as commandline parameters; it does not enumerate interfaces.
#include <unistd.h>
#include <sys/socket.h>
#include <sys/ioctl.h>
#include <netinet/ip.h>
#include <net/if.h>
#include <linux/ethtool.h>
#include <linux/sockios.h>
#include <string.h>
#include <errno.h>
#include <stdio.h>
int ethernet_interface(const char *const name,
int *const index, int *const speed, int *const duplex)
{
struct ifreq ifr;
struct ethtool_cmd cmd;
int fd, result;
if (!name || !*name) {
fprintf(stderr, "Error: NULL interface name.\n");
fflush(stderr);
return errno = EINVAL;
}
if (index) *index = -1;
if (speed) *speed = -1;
if (duplex) *duplex = -1;
fd = socket(AF_INET, SOCK_STREAM, 0);
if (fd == -1) {
const int err = errno;
fprintf(stderr, "%s: Cannot create AF_INET socket: %s.\n", name, strerror(err));
fflush(stderr);
return errno = err;
}
strncpy(ifr.ifr_name, name, sizeof ifr.ifr_name);
ifr.ifr_data = (void *)&cmd;
cmd.cmd = ETHTOOL_GSET;
if (ioctl(fd, SIOCETHTOOL, &ifr) < 0) {
const int err = errno;
do {
result = close(fd);
} while (result == -1 && errno == EINTR);
fprintf(stderr, "%s: SIOCETHTOOL ioctl: %s.\n", name, strerror(err));
return errno = err;
}
if (speed)
*speed = ethtool_cmd_speed(&cmd);
if (duplex)
switch (cmd.duplex) {
case DUPLEX_HALF: *duplex = 0; break;
case DUPLEX_FULL: *duplex = 1; break;
default:
fprintf(stderr, "%s: Unknown mode (0x%x).\n", name, cmd.duplex);
fflush(stderr);
*duplex = -1;
}
if (index && ioctl(fd, SIOCGIFINDEX, &ifr) >= 0)
*index = ifr.ifr_ifindex;
do {
result = close(fd);
} while (result == -1 && errno == EINTR);
if (result == -1) {
const int err = errno;
fprintf(stderr, "%s: Error closing socket: %s.\n", name, strerror(err));
return errno = err;
}
return 0;
}
int main(int argc, char *argv[])
{
int arg, speed, index, duplex;
if (argc < 2 || !strcmp(argv[1], "-h") || !strcmp(argv[1], "--help")) {
fprintf(stderr, "\n");
fprintf(stderr, "Usage: %s [ -h | --help ]\n", argv[0]);
fprintf(stderr, " %s INTERFACE ...\n", argv[0]);
fprintf(stderr, "\n");
return 0;
}
for (arg = 1; arg < argc; arg++) {
if (ethernet_interface(argv[arg], &index, &speed, &duplex))
return 1;
if (index == -1)
printf("%s: (no interface index)", argv[arg]);
else
printf("%s: interface %d", argv[arg], index);
if (speed == -1)
printf(", unknown bandwidth");
else
printf(", %d Mbps bandwidth", speed);
if (duplex == 0)
printf(", half duplex.\n");
else if (duplex == 1)
printf(", full duplex.\n");
else
printf(", unknown mode.\n");
}
return 0;
}
问题?
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