不解释，直接上代码 要求linux环境具备grep和awk（awk可选）

#include 
  
   
#include 
   
     #include 
    
      #include 
     
       int get_if_status(char *if_name) { char buffer[BUFSIZ]; char cmd[100]; FILE *read_fp; int chars_read; int ret =0; memset( buffer, 0, BUFSIZ ); memset( cmd, 0, 100 ); sprintf(cmd, "ifconfig -a | grep %s",if_name); read_fp = popen(cmd, "r"); if ( read_fp != NULL ) { chars_read = fread(buffer, sizeof(char), BUFSIZ-1, read_fp); pclose(read_fp); if (chars_read > 0) { ret = 1; } else { fprintf(stderr, "%s: NO FOUND\r\n",if_name); return 0; } } if(ret == 1) { memset( buffer, 0, BUFSIZ ); memset( cmd, 0, 100 ); sprintf(cmd, "ifconfig |grep %s",if_name); read_fp = popen(cmd, "r"); if ( read_fp != NULL ) { chars_read = fread(buffer, sizeof(char), BUFSIZ-1, read_fp); pclose(read_fp); if (chars_read > 0) { ret = 2; } else { fprintf(stderr, "%s: DOWN\r\n",if_name); return 1; } } } if(ret == 2) { memset( buffer, 0, BUFSIZ ); memset( cmd, 0, 100 ); sprintf(cmd, "ifconfig %s | grep RUNNING | awk '{print $3}'",if_name); read_fp = popen(cmd, "r"); if ( read_fp != NULL ) { chars_read = fread(buffer, sizeof(char), BUFSIZ-1, read_fp); pclose(read_fp); if (chars_read > 0) { fprintf(stderr, "%s: LINKED\r\n",if_name); return 3; } else { fprintf(stderr, "%s: UNPLUGGED\r\n",if_name); return 2; } } } return -1; } int main(int argc, char* argv[]) { int i=0; if(argc != 2) { fprintf(stderr, "usage: %s 
      
       ", argv[0]); return -1; } i = get_if_status(argv[1]); printf( "if_status = %d\n", i ); return 0; } 
      
     
    
   
  

嵌入式编译 mips-linux-gnu-gcc -mips32 -EL -mhard-float -Wall -o netlink netlink.c

测试结果

# ./netlink eth100
eth100: NO FOUND
if_status = 0
# 
# ifconfig eth0 down
# ./netlink eth0  
eth0: DOWN
if_status = 1
# 
# ifconfig eth0 up
# ./netlink eth0
eth0: UNPLUGGED
if_status = 2
#
# ./netlink eth0
eth0: LINKED
if_status = 3