main.c

监视PC机上所有界面的连接活动

#include "main.h"
#define DEBUG 0

int just_list=0, inGB=0, inKB=0, mon=0;

char *make_string(char *str) { // converts bt->kb->mb->gb
	long long num = atoll(str); // for BIG values 
	if (inGB)
		sprintf(str,"%.2f GB ",num/1024./1024/1024);
	else if(inKB)
		sprintf(str,"%.2f KB ",num/1024.);
	else
		sprintf(str,"%.2f MB ",num/1024./1024);
	return str;
}

void trim(char *str) {
	char *p = (char *)str;
	while (*p==' ') p++;
	strcpy(str,p);
}

void parsebuf(char *str) { // parses the input and leaves only digits
	char newstr[40],*p = (char *)str;
	int i=0;
	for (;isdigit(*p);i++,p++) 
		newstr[i]=*p;
	newstr[i]='\0';
	strcpy(str,newstr);
}

void readfile(char *buf, char *dev, char *file) { // read info from file
	char path[80]="/sys/class/net/";
	FILE *fp;
	strcat(strcat(strcat(path,dev),"/statistics/"),file); // create filepath
	if ((fp=fopen(path,"r"))!=NULL) {
		fread(buf,20,1,fp); // read 
		fclose(fp);
		parsebuf(buf); // parse
	} else strcpy(buf,"0");
}

void newprint(char *str) {	// more ellegant way to obtain data
	char dev[16], *p=(char*)str, nstr[100], temp[30];
	int i=0;
	for (;*p!=':';p++,i++)
		dev[i]=*p; // interface name
	dev[i]='\0';
	if (just_list) {
		puts(dev); // list and exit
		return;
	}
	strcat(strcpy(nstr,dev),"\nReceived: "); // concatenate interface, new line and "Received: "
	readfile(temp,dev,"rx_bytes"); // Read received
	strcat(strcat(nstr,make_string(temp)),"("); // concatenate (with conversion to KB,MB,GB) + open bracket for packets
	readfile(temp,dev,"rx_packets"); // Read received packets
	strcat(strcat(nstr,temp)," packets)\nSent: "); // concatenate packets, close bracket, new line + Sent: 
	readfile(temp,dev,"tx_bytes"); // Read sent
	strcat(strcat(nstr,make_string(temp)),"("); // concatenate (with conversion) + open bracket
	readfile(temp,dev,"tx_packets"); // Read sent packets
	strcat(strcat(nstr,temp)," packets)"); // concatenate packets, close bracket
	puts(nstr);
}

void show_help(void) {
	puts("Usage:");
	puts("\tconstat [OPTIONS] <interface>");
	puts("\tExample:");
	puts("\t         constat eth0 -- show info for eth0");
	puts("\t         constat ppp  -- show info for interfaces, matching ppp*");
	puts("\t         constat all  -- show info for all available interfaces");
	puts("\tOptions:");
	puts("\t         -a   -- the same as for 'all'");
	puts("\t         -g   -- show sent/received in GB");
	puts("\t         -h   -- show help and exit (the same as --help)");
	puts("\t         -k   -- show sent/received in KB");
	puts("\t         -l   -- show the list of available interfaces ");
	puts("\t         -m   -- monitors activity (endless 5-second timer)");
	puts("\t         -v   -- show version and exit (the same as --version)");
	puts("\t--help    - show this help and exit");
	puts("\t--version - show version and exit");	
}

void show_version(void) {
	printf("Current version: %s\n",VERSION);
}

int parse_args(char *dev) { // parse arguments
	if (!strcmp(dev,"--version") || !strcmp(dev,"-v")) { // show version info and exit
		show_version();
		return 0;
	}
	
	if (!strcmp(dev,"--help") || !strcmp(dev,"-h")) { // show help and exit
		show_help();
		return 0;
	}
	
	if (!strcmp(dev,"-l")) { // list all, setting just_list (show only devnames) and then set to 'all'
		just_list=1;
		strcpy(dev,"all");
	}
	
	if (!strcmp(dev,"-a")) // show info for all devices
		strcpy(dev,"all");
	
	if (!strcmp(dev,"-g")) // show sent/recieved in GB
		inGB=1;
	
	if (!strcmp(dev,"-k")) // show sent/revieved in KB
		inKB=1;
	
	if (!strcmp(dev,"-m")) 
		mon=1;
	
	return 1;
}

int main(int argc,char *argv[]) {
	char dev[15],filename[]="/proc/net/dev",data[257];
	FILE *fp;
	int i=0, found_flag=0, cont;
	if (argc==1) { // if interface is not specified
		if (DEBUG) { // may be useful for debugging
			puts("Choose interface ('all' to list all data): "); gets(dev);
		} else {
			show_help();
			return 0;
		}
	} else	strcpy(dev,argv[1]);
	cont = parse_args(dev);
	if (argc>2) { // more than one argument specified
		if (strncmp(dev,"-",1)) {
			show_help();
			return 0;
		}
		strcpy(dev,argv[2]);
	}	
	if (!cont) return 0;
	if (mon) { // monitoring, starts an endless timer that shows info for the specified device
		strcat(strcat(argv[0]," "),dev);
		while(1) {
			system("clear");
			system(argv[0]);
			sleep(5);				
		}
	}
	if ((fp = fopen(filename,"r"))!=NULL) { // opening /proc/net/dev
		for (;i<2;i++) fgets(data,256,fp); //scroll 2 first lines
		while(fgets(data,256,fp)) { // iterating over the file to find what we need
			trim(data);	// remove whitespaces from the beginning of the line
			if (!strcmp(dev,"all")) 
				newprint(data);  // if we chose 'all' then we print info for every device
			else 
				if (!strncmp(data,dev,strlen(dev)))
					newprint(data); // otherwise we compare the device and decide whether to show it or not
			if (!strcmp(dev,"all") || !strncmp(data,dev,strlen(dev))) 
				found_flag=1; // if we have found what we need, set the flag to 1
		}
		if(!found_flag) puts("Error: interface not found"); // if nothing found - error
		fclose(fp);
	} else puts("Error: failed to obtain data"); // failed to open
	return 0;
}