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Add a c source file that will be needed for dhcp serving (recvmsg is daunting from perl)

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git-svn-id: https://svn.code.sf.net/p/xcat/code/xcat-core/trunk@10667 8638fb3e-16cb-4fca-ae20-7b5d299a9bcd
This commit is contained in:
jbjohnso 2011-09-28 20:22:00 +00:00
parent a5adea2fd4
commit 5743838edb
1 changed files with 91 additions and 0 deletions
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91
src/proxydhcp.c Normal file
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#include <stdio.h>
#include <netdb.h>
#include <string.h>
#include <sys/socket.h>
#include <sys/types.h>
#include <stdlib.h>
#include <errno.h>
#include <netinet/in.h>
int main() {
int serverfd,port;
int getpktinfo = 1;
struct addrinfo hint, *res;
char cmsg[CMSG_SPACE(sizeof(struct in_pktinfo))];
char clientpacket[1024];
struct sockaddr_in clientaddr;
struct msghdr msg;
struct cmsghdr *cmsgptr;
struct iovec iov[1];
unsigned int myip;
char *txtptr;
iov[0].iov_base = clientpacket;
iov[0].iov_len = 1024;
memset(&msg,0,sizeof(msg));
memset(&clientaddr,0,sizeof(clientaddr));
msg.msg_name=&clientaddr;
msg.msg_namelen = sizeof(clientaddr);
msg.msg_iov = iov;
msg.msg_iovlen = 1;
msg.msg_control=&cmsg;
msg.msg_controllen = sizeof(cmsg);
char bootpmagic[4] = {0x63,0x82,0x53,0x63};
int pktsize;
int doexit=0;
port = 4011;
memset(&hint,0,sizeof(hint));
hint.ai_family = PF_INET; /* Would've done UNSPEC, but it doesn't work right and this is heavily v4 specific anyway */
hint.ai_socktype = SOCK_DGRAM;
hint.ai_flags = AI_PASSIVE;
getaddrinfo(NULL,"4011",&hint,&res);
serverfd = socket(res->ai_family, res->ai_socktype, res->ai_protocol);
if (!serverfd) { fprintf(stderr,"That's odd...\n"); }
setsockopt(serverfd,IPPROTO_IP,IP_PKTINFO,&getpktinfo,sizeof(getpktinfo));
if (bind(serverfd,res->ai_addr ,res->ai_addrlen) < 0) {
fprintf(stderr,"Unable to bind 4011");
exit(1);
}
while (!doexit) {
pktsize = recvmsg(serverfd,&msg,0);
if (pktsize < 320) {
continue;
}
if (clientpacket[0] != 1 || memcmp(clientpacket+0xec,bootpmagic,4)) {
continue;
}
for (cmsgptr = CMSG_FIRSTHDR(&msg); cmsgptr != NULL; cmsgptr = CMSG_NXTHDR(&msg,cmsgptr)) {
if (cmsgptr->cmsg_level == IPPROTO_IP && cmsgptr->cmsg_type == IP_PKTINFO) {
myip = ((struct in_pktinfo*)(CMSG_DATA(cmsgptr)))->ipi_addr.s_addr;
}
}
clientpacket[0] = 2; //change to a reply
myip = htonl(myip); //endian neutral change
clientpacket[0x14] = (myip>>24)&0xff; //maybe don't need to do this, maybe assigning the whole int would be better
clientpacket[0x15] = (myip>>16)&0xff;
clientpacket[0x16] = (myip>>8)&0xff;
clientpacket[0x17] = (myip)&0xff;
txtptr = clientpacket+0x6c;
strncpy(txtptr,"bootmgfw.efi",128); // keeping 128 in there just in case someone changes the string
clientpacket[0xf0]=0x35; //DHCP MSG type
clientpacket[0xf1]=0x1; // LEN of 1
clientpacket[0xf2]=0x5; //DHCP ACK
clientpacket[0xf3]=0x36; //DHCP server identifier
clientpacket[0xf4]=0x4; //DHCP server identifier length
clientpacket[0xf5] = (myip>>24)&0xff; //maybe don't need to do this, maybe assigning the whole int would be better
clientpacket[0xf6] = (myip>>16)&0xff;
clientpacket[0xf7] = (myip>>8)&0xff;
clientpacket[0xf8] = (myip)&0xff;
clientpacket[0xf9] = 0xfc; // dhcp 252 'proxy', but coopeted by bootmgfw, it's actually suggesting the boot config file
clientpacket[0xfa] = 9; //length of 9
txtptr = clientpacket+0xfb;
strncpy(txtptr,"Boot/BCD",8);
clientpacket[0x103]=0;
clientpacket[0x104]=0xff;
sendto(serverfd,clientpacket,pktsize,0,(struct sockaddr*)&clientaddr,sizeof(clientaddr));
}
}