/*
 * I'm rubber, you're glue.
 * Whatever you say bounces off me and sticks to you.
 */

#include <u.h>
#include <libc.h>
#include <ip.h>
#include "a1.h"

int chatty = 0;

void
usage(void)
{
	fprint(2, "usage: snmpmirror udp!*!snmp [redirect-host]\n");
	exits("usage");
}

char*
ct(ulong t)
{
	char *p;

	p = ctime(t);
	if(p[strlen(p)-1] == '\n')
		p[strlen(p)-1] = '\0';
	return p;
}

void
main(int argc, char **argv)
{
	int nfd, fd, n;
	uchar buf[65536];
	char ip[40];
	char *addr, *remote, *a;
	Dir *d;
	Snmp s, r;

	fmtinstall('I', eipfmt);
	fmtinstall('E', eipfmt);

	ARGBEGIN{
	default:
		usage();
	}ARGEND

	addr = remote = nil;
	switch(argc){
	case 2:
		remote = argv[1];
	case 1:
		addr = argv[0];
		break;
	default:
		usage();
	}

	fd = openlisten(addr);
	while((n = read(fd, buf, sizeof buf)) > 0){
		print("%s %I/%d -> %I/%d ", ct(time(0)),
			buf, nhgets(buf+16+16),
			buf+16, nhgets(buf+16+16+2));
		if(Sparse(buf+36, n-36, &s) < 0){
			print("format error\n");
			continue;
		}
		Sprint(&s);

		if(remote)
			a = remote;
		else{
			snprint(ip, sizeof ip, "%I", buf);
			a = ip;
		}
		if((nfd = dial(netmkaddr(a, "udp", "snmp"), 0, 0, 0)) < 0){
			print("\tcannot dial '%s': %r\n", a);
			continue;
		}
		print("\tredirect %s\n", a);
		if(dosnmp(nfd, &s, &r) < 0){
			print("\tsnmp failed: %r\n");
			close(nfd);
			/*
			 * Discard any packets that arrived while we were 
			 * sending things out -- they might be remirrored
			 * copies of what we were sending.
			 */
			while((d = dirfstat(fd)) != nil && d->length > 0){
				free(d);
				if(read(fd, buf, sizeof buf) <= 0)
					break;
				print("discard\n");
			}
			free(d);
			continue;
		}
		close(nfd);

		print("%s %I/%d <- %I/%d ", ctime(time(0)),
			buf, nhgets(buf+16+16),
			buf+16, nhgets(buf+16+16+2));
		Sprint(&r);
		n = Sunparse(&r, buf+36, sizeof(buf)-36);
		if(write(fd, buf, n+36) != n+36)
			print("\twrite failed: %r\n");
	}
	print("exiting: %d %r\n", n);
	exits(nil);
}