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Initial implementation of sshchat client as a simple forwarder (with bugs)

Dario Rodriguez authored on 16/12/2015 21:52:13
Showing 5 changed files
src/.sshchat
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+myid
src/Makefile
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+CC=gcc
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+CFLAGS=-g -Wall -I../../webkernel/src
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+LDFLAGS=
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+
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+all: sshchat
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+
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+sshchat: sshchat.o sbuf.o socklib.o
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+	$(CC) sshchat.o sbuf.o socklib.o -o sshchat
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+
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+sbuf.o: ../../webkernel/src/sbuf.c
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+	$(CC) $(CFLAGS) $(LDFLAGS) -c ../../webkernel/src/sbuf.c -o sbuf.o
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+
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+socklib.o: ../../webkernel/src/socklib.c
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+	$(CC) $(CFLAGS) $(LDFLAGS) -c ../../webkernel/src/socklib.c -o socklib.o
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+
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+clean:
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+	rm -f sshchat *.o
src/sshchat.c
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+/*
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+ * sshchat.c
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+ *
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+ * Client component of sshchat, connects to server, identifies itself using ~/.sshchat file and forwards stdin/stdout.
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+ *
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+ * Author: Dario Rodriguez dario@softhome.net
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+ * This program is licensed under the terms of the GPL v2.1+
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+ */
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+
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+#include <stdlib.h>
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+#include <stdio.h>
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+#include <unistd.h>
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+#include <string.h>
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+#include <sys/types.h>
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+#include <sys/stat.h>
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+#include <fcntl.h>
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+
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+#include "socklib.h"
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+#include "sbuf.h"
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+
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+#include "sshchat.h"
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+
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+#define MAXIDSIZE 128
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+#define CONNTIMEOUT 2000
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+#define SELECTTIMEOUT 1000
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+
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+#define BUFSIZE 16384
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+
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+#define INFD 0
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+#define OUTFD 1
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+
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+int
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+main(int argc, char *argv[])
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+{
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+	char id[MAXIDSIZE];
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+	int fd,n;
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+	char *ptr;
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+	char *host,port;
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+	long hostsize;
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+	int socket;
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+	sbuf *c2s,*s2c;
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+	sselect *ssel;
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+	int forcedexit;
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+	int readfds[2];
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+	int writefds[2];
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+	int nreadfds;
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+	int nwritefds;
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+	int i;
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+	int queued;
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+	/* get the id */
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+	if((fd=open(".sshchat",O_RDONLY))==-1)
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+		return(-1); /* error */
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+	if((n=read(fd,id,MAXIDSIZE))<1 || id[0]=='\n') {
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+		close(fd),fd=-1;
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+		return(-2); /* no id */
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+	}
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+	close(fd),fd=-1;
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+	id[(n>=MAXIDSIZE)?MAXIDSIZE-1:n]='\0';
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+	if((ptr=strchr(id,'\n'))!=NULL)
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+		*ptr='\0';
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+	/* open socket to server */
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+	if((host=ipv4_genip("127.0.0.1",&hostsize))==NULL)
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+		return(-3); /* couldn't resolv localhost */
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+	if((port=ipv4_genport("sshchat",SERVERPORT))==-1) {
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+		free(host),host=NULL;
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+		return(-4); /* couldn't resolv port */
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+	}
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+	if((socket=ipv4_preconnect(host,hostsize,port))==-1) {
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+		free(host),host=NULL;
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+		return(-5); /* couldn't connect to localhost (1) */
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+	}
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+	if(ipv4_connect(socket,CONNTIMEOUT)==-1) {
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+		free(host),host=NULL;
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+		return(-6); /* couldn't connect to localhost (2) */
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+	}
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+	ipv4_postconnect(socket);
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+	free(host),host=NULL,hostsize=0;
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+	/* alloc I/O buffers */
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+	if((c2s=sbuf_init(BUFSIZE))==NULL || (s2c=sbuf_init(BUFSIZE))==NULL) {
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+		close(socket),socket=-1,sbuf_free(c2s),c2s=NULL;
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+		return(-7); /* couldn't alloc buffers */
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+	}
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+	if((ssel=sselect_init())==NULL) {
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+		close(socket),socket=-1,sbuf_free(c2s),c2s=NULL,sbuf_free(s2c),s2c=NULL;
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+		return(-8); /* couldn't alloc select struct */
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+	}
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+	/* prefeed the identification */
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+	sbuf_addstr(c2s,id);
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+	sbuf_addstr(c2s,"\n");
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+	/* forward data */
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+	forcedexit=0;
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+	while(!forcedexit) {
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+		sselect_reset(ssel);
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+		if(sbuf_count(c2s)<BUFSIZE)
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+			sselect_addread(ssel,INFD,NULL);
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+		if(sbuf_count(c2s)>0)
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+			sselect_addwrite(ssel,socket,NULL);
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+		if(sbuf_count(s2c)>0)
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+			sselect_addwrite(ssel,OUTFD,NULL);
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+		if(sbuf_count(s2c)<BUFSIZE)
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+			sselect_addread(ssel,socket,NULL);
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+		if(sselect_wait(ssel,SELECTTIMEOUT)<1)
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+			continue;
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+		nreadfds=sselect_getread(ssel,readfds,sizeof(readfds)/sizeof(readfds[1]));
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+		nwritefds=sselect_getwrite(ssel,writefds,sizeof(writefds)/sizeof(writefds[1]));
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+		for(i=0;i<nreadfds;i++) {
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+			if(readfds[i]==INFD && sbuf_count(c2s)<BUFSIZE) {
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+				if((queued=sock_queued(readfds[i]))==0) {
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+					forcedexit=1;
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+					break;
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+				}
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+				sbuf_discard(c2s);
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+				sbuf_fill(c2s,INFD,queued);
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+			}
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+			if(readfds[i]==socket && sbuf_count(s2c)<BUFSIZE) {
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+				if((queued=sock_queued(readfds[i]))==0) {
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+					forcedexit=1;
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+					break;
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+				}
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+				sbuf_discard(s2c);
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+				sbuf_fill(s2c,socket,queued);
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+			}
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+		}
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+		for(i=0;i<nwritefds;i++) {
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+			if(writefds[i]==OUTFD && sbuf_count(s2c)>0)
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+				sbuf_send(s2c,OUTFD,sbuf_count(s2c));
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+			if(writefds[i]==socket && sbuf_count(c2s)>0)
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+				sbuf_send(c2s,socket,sbuf_count(c2s));
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+		}
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+	}
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+	/* normal exit */
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+	close(socket),socket=-1;
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+	sbuf_free(c2s),c2s=NULL;
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+	sbuf_free(s2c),s2c=NULL;
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+	sselect_free(ssel),ssel=NULL;
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+	return(0);
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+}
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+
src/sshchat.h
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+/*
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+ * sshchat.h
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+ *
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+ * Common constants for server and client parts of sshchat.
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+ *
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+ * Author: Dario Rodriguez dario@softhome.net
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+ * This program is licensed under the terms of the GPL v2.1+
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+ */
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+
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+#define SERVERPORT 4798
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+
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+
src/sshchatd.c
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+/*
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+ * sshchatd.c
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+ *
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+ * Server component of sshchat, serves as mailbox for disconnected users.
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+ *
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+ * Author: Dario Rodriguez dario@softhome.net
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+ * This program is licensed under the terms of the GPL v2.1+
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+ */
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+
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+