forked from mirrors/tftp-hpa-google
153 lines
3.8 KiB
C
153 lines
3.8 KiB
C
/* $Id$ */
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/* ----------------------------------------------------------------------- *
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*
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* Copyright 2001 H. Peter Anvin - All Rights Reserved
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*
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* This program is free software available under the same license
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* as the "OpenBSD" operating system, distributed at
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* http://www.openbsd.org/.
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*
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* ----------------------------------------------------------------------- */
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/*
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* recvfrom.c
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*
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* Emulate recvfrom() using recvmsg(), but try to capture the local address
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* since some TFTP clients consider it an error to get the reply from another
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* IP address than the request was sent to.
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*
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*/
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#include "config.h" /* Must be included first! */
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#include "recvfrom.h"
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#include "tftpsubs.h"
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#ifdef HAVE_MACHINE_PARAM_H
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#include <machine/param.h> /* Needed on some versions of FreeBSD */
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#endif
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#if defined(HAVE_RECVMSG) && defined(HAVE_MSGHDR_MSG_CONTROL)
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#include <sys/uio.h>
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#ifdef IP_PKTINFO
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# ifndef HAVE_STRUCT_IN_PKTINFO
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# ifdef __linux__
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/* Assume this version of glibc simply lacks the definition */
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struct in_pktinfo {
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int ipi_ifindex;
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struct in_addr ipi_spec_dst;
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struct in_addr ipi_addr;
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};
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# else
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# undef IP_PKTINFO /* No definition, no way to get it */
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# endif
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# endif
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#endif
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#ifndef CMSG_LEN
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# define CMSG_LEN(size) (sizeof(struct cmsghdr) + (size))
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#endif
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#ifndef CMSG_SPACE
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# define CMSG_SPACE(size) (sizeof(struct cmsghdr) + (size))
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#endif
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int
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myrecvfrom(int s, void *buf, int len, unsigned int flags,
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struct sockaddr *from, int *fromlen,
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struct sockaddr_in *myaddr)
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{
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struct msghdr msg;
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struct iovec iov;
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int n;
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struct cmsghdr *cmptr;
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union {
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struct cmsghdr cm;
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#ifdef IP_PKTINFO
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char control[CMSG_SPACE(sizeof(struct in_addr)) +
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CMSG_SPACE(sizeof(struct in_pktinfo))];
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#else
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char control[CMSG_SPACE(sizeof(struct in_addr))];
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#endif
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} control_un;
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int on = 1;
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#ifdef IP_PKTINFO
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struct in_pktinfo pktinfo;
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#endif
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/* Try to enable getting the return address */
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#ifdef IP_RECVDSTADDR
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setsockopt(s, IPPROTO_IP, IP_RECVDSTADDR, &on, sizeof(on));
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#endif
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#ifdef IP_PKTINFO
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setsockopt(s, IPPROTO_IP, IP_PKTINFO, &on, sizeof(on));
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#endif
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bzero(&msg, sizeof msg); /* Clear possible system-dependent fields */
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msg.msg_control = control_un.control;
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msg.msg_controllen = sizeof(control_un.control);
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msg.msg_flags = 0;
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msg.msg_name = from;
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msg.msg_namelen = *fromlen;
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iov.iov_base = buf;
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iov.iov_len = len;
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msg.msg_iov = &iov;
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msg.msg_iovlen = 1;
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if ( (n = recvmsg(s, &msg, flags)) < 0 )
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return n; /* Error */
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*fromlen = msg.msg_namelen;
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if ( myaddr ) {
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bzero(myaddr, sizeof(struct sockaddr_in));
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myaddr->sin_family = AF_INET;
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if ( msg.msg_controllen < sizeof(struct cmsghdr) ||
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(msg.msg_flags & MSG_CTRUNC) )
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return n; /* No information available */
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for ( cmptr = CMSG_FIRSTHDR(&msg) ; cmptr != NULL ;
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cmptr = CMSG_NXTHDR(&msg, cmptr) ) {
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#ifdef IP_RECVSTDADDR
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if ( cmptr->cmsg_level == IPPROTO_IP &&
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cmptr->cmsg_type == IP_RECVDSTADDR ) {
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memcpy(&myaddr->sin_addr, CMSG_DATA(cmptr),
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sizeof(struct in_addr));
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}
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#endif
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#ifdef IP_PKTINFO
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if ( cmptr->cmsg_level == IPPROTO_IP &&
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cmptr->cmsg_type == IP_PKTINFO ) {
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memcpy(&pktinfo, CMSG_DATA(cmptr), sizeof(struct in_pktinfo));
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memcpy(&myaddr->sin_addr, &pktinfo.ipi_addr, sizeof(struct in_addr));
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}
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#endif
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}
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}
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return n;
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}
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#else /* pointless... */
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int
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myrecvfrom(int s, void *buf, int len, unsigned int flags,
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struct sockaddr *from, int *fromlen,
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struct sockaddr_in *myaddr)
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{
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/* There is no way we can get the local address, fudge it */
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bzero(myaddr, sizeof(struct sockaddr_in));
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myaddr->sin_family = AF_INET;
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myaddr->sin_port = htons(IPPORT_TFTP);
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bzero(&myaddr->sin_addr, sizeof(myaddr->sin_addr));
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return recvfrom(s,buf,len,flags,from,fromlen);
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}
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#endif
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