socklib.c

#include <sys/types.h>
#include <unistd.h>
#include <sys/time.h>
#include <string.h>
#include <stdlib.h>
#include <errno.h>

#include <fcntl.h>

#ifndef __MINGW32__
#include <arpa/inet.h>
#include <netdb.h>
#include <net/if.h>
#include <sys/ioctl.h>

#else /* __MINGW32__ */

#include <ws2tcpip.h>
#define ioctl ioctlsocket

#include <iprtrmib.h>
#include <iphlpapi.h>

#endif /* __MINGW32__ */

#include "log.h"
#include "socklib.h"
#include "util.h"

#ifndef SOL_IP
#define SOL_IP IPPROTO_IP
#endif

#ifdef __linux__

#include <linux/types.h>

typedef unsigned long long u64;
typedef unsigned int u32;
typedef unsigned short u16;
typedef unsigned char u8;

#include <linux/ethtool.h>
#include <linux/sockios.h>

#endif

// for Darwin
#ifdef _SIZEOF_ADDR_IFREQ
    #define IFREQ_SIZE(a) _SIZEOF_ADDR_IFREQ(a)
#endif

#ifndef DEBUG
# define DEBUG 0
#endif

#ifdef LOSSTEST
/**
 * Packet loss/swap testing...
 */
long int write_loss = 0;
long int read_loss = 0;
long int read_swap = 0;
unsigned int seed=0;

int loseSendPacket(void) {
    if(write_loss) {
	long r = random();
	if(r < write_loss)
	    return 1;
    }
    return 0;
}

#define STASH_SIZE 64

static int stashed;
static struct packetStash {
    unsigned char data[4092];
    int size;
} packetStash[STASH_SIZE];

/**
 * Lose a packet
 */
void loseRecvPacket(int s) {
    if(read_loss) {
	while(random() < read_loss) {
	    int x;
	    flprintf("Losing packet\n");
	    recv(s, (void *) &x, sizeof(x),0);
	}
    }
    if(read_swap) {
	while(stashed < STASH_SIZE && random() < read_swap) {
	    int size;
	    flprintf("Stashing packet %d\n", stashed);
	    size = recv(s, packetStash[stashed].data, 
			sizeof(packetStash[stashed].data),0);
	    packetStash[stashed].size = size;
	    stashed++;
	}
    }
}

/**
 * bring stored packet back up...
 */
int RecvMsg(int s, struct msghdr *msg, int flags) {
    if(read_swap && stashed) {
	if(random() / stashed < read_swap) {
	    int slot = random() % stashed;
	    int iovnr;
	    char *data = packetStash[slot].data;
	    int totalLen = packetStash[slot].size;
	    int retBytes=0;
	    flprintf("Bringing out %d\n", slot);
	    for(iovnr=0; iovnr < msg->msg_iovlen; iovnr++) {
		int len = msg->msg_iov[iovnr].iov_len;
		if(len > totalLen)
		    len = totalLen;
		memcpy(msg->msg_iov[iovnr].iov_base, data, len);
		totalLen -= len;
		data += len;
		retBytes += len;
		if(totalLen == 0)
		    break;
	    }
	    packetStash[slot]=packetStash[stashed];
	    stashed--;
	    return retBytes;
	}
    }
    return recvmsg(s, msg, flags);
}

void setWriteLoss(char *l) {
    write_loss = (long) (atof(l) * RAND_MAX);
}

void setReadLoss(char *l) {
    read_loss = (long) (atof(l) * RAND_MAX);
}

void setReadSwap(char *l) {
    read_swap = (long) (atof(l) * RAND_MAX);
}


void srandomTime(int printSeed) {
    struct timeval tv;
    long seed;
    gettimeofday(&tv, 0);
    seed = (tv.tv_usec * 2000) ^ tv.tv_sec;
    if(printSeed)
	flprintf("seed=%ld\n", seed);
    srandom(seed);
}
#endif

/**
 * If queue gets almost full, slow down things
 */
void doAutoRateLimit(int sock, int dir, int qsize, int size)
{
    while(1) {
	int r = udpc_getCurrentQueueLength(sock);
	if(dir)
	    r = qsize - r;
	if(r < qsize / 2 - size)
	    return;
#if DEBUG
	flprintf("Queue full %d/%d... Waiting\n", r, qsize);
#endif
	usleep(2500);
    }
}


/* makes a socket address */
int makeSockAddr(char *hostname, short port, struct sockaddr_in *addr)
{
    struct hostent *host;

    memset ((char *) addr, 0, sizeof(struct sockaddr_in));
    if (hostname && *hostname) {
	char *inaddr;
	int len;

	host = gethostbyname(hostname);
	if (host == NULL) {
	    udpc_fatal(1, "Unknown host %s\n", hostname);
	}
	
	inaddr = host->h_addr_list[0];
	len = host->h_length;
	memcpy((void *)&((struct sockaddr_in *)addr)->sin_addr, inaddr, len);
    }

    ((struct sockaddr_in *)addr)->sin_family = AF_INET;
    ((struct sockaddr_in *)addr)->sin_port = htons(port);
    return 0;
}

#ifdef __MINGW32__
static int inet_aton(const char *address, struct in_addr *ip) {
    unsigned long result=0;
    int j;
    for(j=0; j<4; j++) {
	int digit;

	if(!*address)
	    return 0;
	digit = strtoul(address, (char**)&address, 10);
	result = (result << 8) + digit;
	if(j < 3) {
	    if(*address == '.')
		address++;
	    else
		return 0;
	}
    }
    if(*address)
	return 0;
    ip->s_addr = htonl(result);
    return ip->s_addr;
}

typedef unsigned long in_addr_t;
#endif /* __MINGW32__ */

static int initSockAddress(addr_type_t addr_type,
			   net_if_t *net_if, 
			   in_addr_t ip,
			   unsigned short port, 
			   struct sockaddr_in *addr) {
    memset ((char *) addr, 0, sizeof(struct sockaddr_in));
    addr->sin_family = AF_INET;
    addr->sin_port = htons(port);

    if(!net_if && addr_type != ADDR_TYPE_MCAST)
	udpc_fatal(1, "initSockAddr without ifname\n");

    switch(addr_type) {
    case ADDR_TYPE_UCAST:
	addr->sin_addr = net_if->addr;
	break;
    case ADDR_TYPE_BCAST:
	addr->sin_addr = net_if->bcast;
	break;
    case ADDR_TYPE_MCAST:
	addr->sin_addr.s_addr = ip;
	break;
    }
    return 0;
}

int getMyAddress(net_if_t *net_if, struct sockaddr_in *addr) {
    return initSockAddress(ADDR_TYPE_UCAST, net_if, INADDR_ANY, 0, addr);
}


int getBroadCastAddress(net_if_t *net_if, struct sockaddr_in *addr, 
			short port){
    int r= initSockAddress(ADDR_TYPE_BCAST, net_if, INADDR_ANY, port, addr);
    if(addr->sin_addr.s_addr == 0) {
      /* Quick hack to make it work for loopback */
      struct sockaddr_in ucast;
      initSockAddress(ADDR_TYPE_UCAST, net_if, INADDR_ANY, port, &ucast);

      if((ntohl(ucast.sin_addr.s_addr) & 0xff000000) == 0x7f000000)
	addr->sin_addr.s_addr = ucast.sin_addr.s_addr;
    }
    return r;
}

static int mcastListen(int sock, net_if_t *net_if, struct sockaddr_in *addr);

static int safe_inet_aton(char *address, struct in_addr *ip) {
    if(!inet_aton(address, ip))
	udpc_fatal(-1, "Bad address %s", address);
    return 0;
}


int getMcastAllAddress(struct sockaddr_in *addr, char *address, short port){
    struct in_addr ip;
    int ret;

    if(address == NULL || address[0] == '\0')
	inet_aton("224.0.0.1", &ip);
    else {
	if((ret=safe_inet_aton(address, &ip))<0)
	   return ret;
    }
    return initSockAddress(ADDR_TYPE_MCAST, NULL, ip.s_addr, port, addr);
}


int doSend(int s, void *message, size_t len, struct sockaddr_in *to) {
/*    flprintf("sent: %08x %d\n", *(int*) message, len);*/
#ifdef LOSSTEST
    loseSendPacket();
#endif
    return sendto(s, message, len, 0, (struct sockaddr*) to, sizeof(*to));
}

int doReceive(int s, void *message, size_t len, 
	      struct sockaddr_in *from, int portBase) {
    socklen_t slen;
    int r;
    unsigned short port;
    char ipBuffer[16];

    slen = sizeof(*from);
#ifdef LOSSTEST
    loseRecvPacket(s);
#endif
    r = recvfrom(s, message, len, 0, (struct sockaddr *)from, &slen);
    if (r < 0)
	return r;
    port = ntohs(from->sin_port);
    if(port != RECEIVER_PORT(portBase) && port != SENDER_PORT(portBase)) {
	udpc_flprintf("Bad message from port %s.%d\n", 
		      getIpString(from, ipBuffer),
		      ntohs(((struct sockaddr_in *)from)->sin_port));
	return -1;
    }
/*    flprintf("recv: %08x %d\n", *(int*) message, r);*/
    return r;
}

int getSendBuf(int sock) {
    int bufsize;
    size_t len=sizeof(int);
    if(getsockopt(sock, SOL_SOCKET, SO_SNDBUF, (char*)&bufsize, &len) < 0)
	return -1;
    return bufsize;
}

void setSendBuf(int sock, unsigned int bufsize) {
    if(setsockopt(sock, SOL_SOCKET, SO_SNDBUF, (char*)&bufsize, sizeof(bufsize))< 0)
	perror("Set send buffer");
}

unsigned int getRcvBuf(int sock) {
    unsigned int bufsize;
    size_t len=sizeof(int);
    if(getsockopt(sock, SOL_SOCKET, SO_RCVBUF, (char *)&bufsize, &len) < 0)
	return -1;
    return bufsize;
}

void setRcvBuf(int sock, unsigned int bufsize) {
    if(setsockopt(sock, SOL_SOCKET, SO_RCVBUF, 
		  (char*) &bufsize, sizeof(bufsize))< 0)
	perror("Set receiver buffer");
}

int getCurrentQueueLength(int sock) {
#ifdef TIOCOUTQ
    int length;
    if(ioctl(sock, TIOCOUTQ, &length) < 0)
	return -1;
    return length;
#else
    return -1;
#endif
}


int setSocketToBroadcast(int sock) {
    /* set the socket to broadcast */
    int p = 1;
    return setsockopt(sock, SOL_SOCKET, SO_BROADCAST, (char *)&p, sizeof(int));
}

int setTtl(int sock, int ttl) {
    /* set the socket to broadcast */
    return setsockopt(sock, SOL_IP, IP_MULTICAST_TTL, (char*)&ttl, sizeof(int));
}

#ifdef SIOCGIFINDEX
# define IP_MREQN ip_mreqn
#else
# define IP_MREQN ip_mreq
#endif

#define getSinAddr(addr) (((struct sockaddr_in *) addr)->sin_addr)


/**
 * Fill in the mreq structure with the given interface and address
 */
static int fillMreq(int sock, net_if_t *net_if, struct in_addr addr,
		    struct IP_MREQN *mreq) {
#ifdef SIOCGIFINDEX
    mreq->imr_ifindex = net_if->index;
    mreq->imr_address.s_addr = 0;
#else
    mreq->imr_interface = net_if->addr;
#endif
    mreq->imr_multiaddr = addr;

    return 0;
}

/**
 * Perform a multicast operation
 */
static int mcastOp(int sock, net_if_t *net_if, struct in_addr addr,
		   int code, char *message) {
    struct IP_MREQN mreq;
    int r;
    
    fillMreq(sock, net_if, addr, &mreq);
    r = setsockopt(sock, SOL_IP, code, (char*)&mreq, sizeof(mreq));
    if(r < 0) {
	perror(message);
	exit(1);
    }
    return 0;
}


/*
struct in_addr getSinAddr(struct sockaddr_in *addr) {
    return ((struct sockaddr_in *) addr)->sin_addr;
}
*/

/**
 * Set socket to listen on given multicast address Not 100% clean, it
 * would be preferable to make a new socket, and not only subscribe it
 * to the multicast address but also _bind_ to it. Indeed, subscribing
 * alone is not enough, as we may get traffic destined to multicast
 * address subscribed to by other apps on the machine. However, for
 * the moment, we skip this concern, as udpcast's main usage is
 * software installation, and in that case it runs on an otherwise
 * quiet system.
 */
static int mcastListen(int sock, net_if_t *net_if, struct sockaddr_in *addr) {
    return mcastOp(sock, net_if, getSinAddr(addr), IP_ADD_MEMBERSHIP,
		   "Subscribe to multicast group");
}


int setMcastDestination(int sock, net_if_t *net_if, struct sockaddr_in *addr) {
#ifdef WINDOWS
    int r;
    struct sockaddr_in interface_addr;
    struct in_addr if_addr;
    getMyAddress(net_if, &interface_addr);
    if_addr = getSinAddr(&interface_addr);
    r = setsockopt (sock, IPPROTO_IP, IP_MULTICAST_IF, 
		    (char *) &if_addr, sizeof(if_addr));
    if(r < 0)
	fatal(1, "Set multicast send interface");
    return 0;
#else
    /* IP_MULTICAST_IF not correctly supported on Cygwin */
    return mcastOp(sock, net_if, getSinAddr(addr), IP_MULTICAST_IF,
		   "Set multicast send interface");
#endif
}


#ifdef __MINGW32__
static MIB_IFROW *getIfRow(MIB_IFTABLE *iftab, DWORD dwIndex) {
    int j;
    
    /* Find the corresponding interface row (for name and
     * MAC address) */
    for(j=0; j<iftab->dwNumEntries; j++) {
	MIB_IFROW *ifrow = &iftab->table[j];
	/* eth0, eth1, ... */
	if(ifrow->dwIndex == dwIndex)
	    return ifrow;
    }
    return NULL;
}

static char *fmtName(MIB_IFROW *ifrow) {
    char *out;
    int l = ifrow->dwDescrLen+1;
    if(ifrow->dwPhysAddrLen)
	l+=2+3*ifrow->dwPhysAddrLen;
    out = malloc(ifrow->dwDescrLen+l+1);
    if(!out)
	return NULL;
    strncpy(out, ifrow->bDescr, ifrow->dwDescrLen);
    out[ifrow->dwDescrLen]='\0';

    if(ifrow->dwPhysAddrLen) {
	int k;
	char *ptr=out+strlen(out);
	strcpy(ptr, " (");
	ptr+=2;
	for(k=0; k<ifrow->dwPhysAddrLen; k++) {
	    if(k)
		*ptr++='-';
	    sprintf(ptr, "%02x", 255 & ifrow->bPhysAddr[k]);
	    ptr += 2;
	}
	strcpy(ptr, ")");
    }
    return out;
}
#endif /* __MINGW32__ */

#ifndef __MINGW32__
/**
 * Tests whether the given card has link
 * 0 no
 * 1 yes
 * -1 unknown
 */
static int hasLink(int s, const char *ifname) {

#ifdef ETHTOOL_GLINK
  struct ifreq ifr;
  struct ethtool_value edata;

  edata.cmd = ETHTOOL_GLINK;

  strncpy(ifr.ifr_name, ifname, sizeof(ifr.ifr_name)-1);
  ifr.ifr_data = (char *) &edata;

  if(ioctl(s, SIOCETHTOOL, &ifr) == -1) {
    /* Operation not supported */
    return -1;
  } else {
    return edata.data;
  }
#else
  return -1;
#endif
}
#endif

/**
 * Tests whether the given card operates in full duplex mode
 * 0 no
 * 1 yes
 * -1 unknown
 */
int isFullDuplex(int s, const char *ifname) {

#ifdef ETHTOOL_GLINK
  struct ifreq ifr;
  struct ethtool_cmd ecmd;

  ecmd.cmd = ETHTOOL_GSET;

  strncpy(ifr.ifr_name, ifname, sizeof(ifr.ifr_name)-1);
  ifr.ifr_data = (char *) &ecmd;

  if(ioctl(s, SIOCETHTOOL, &ifr) == -1) {
    /* Operation not supported */
    return -1;
  } else {
    return ecmd.duplex;
  }
#else
  return -1;
#endif
}


/**
 * Canonize interface name. If attempt is not NULL, pick the interface
 * which has that address.
 * If attempt is NULL, pick interfaces in the following order of preference
 * 1. eth0
 * 2. Anything starting with eth0:
 * 3. Anything starting with eth
 * 4. Anything else
 * 5. localhost
 * 6. zero address
 */
net_if_t *getNetIf(const char *wanted) {
#ifndef __MINGW32__
	struct ifreq ibuf[100];
	struct ifreq *ifrp, *ifend, *chosen;
	struct ifconf ifc;
	int s;
#else /* __MINGW32__ */
	int i;

	int etherNo=-1;
	int wantedEtherNo=-2; /* Wanted ethernet interface */

	MIB_IPADDRTABLE *iptab=NULL;
	MIB_IFTABLE *iftab=NULL;

	MIB_IPADDRROW *iprow, *chosen=NULL;
	MIB_IFROW *chosenIf=NULL;
	WORD wVersionRequested; /* Version of Winsock to load */
	WSADATA wsaData; /* Winsock implementation details */
	ULONG a;

	int r;
#endif /* __MINGW32__ */

	int lastGoodness=0;
	struct in_addr wantedAddress;
	int isAddress=0;
	int wantedLen=0;
	net_if_t *net_if;

	if(wanted == NULL) {
	    wanted = getenv("IFNAME");
	}

	if(wanted && inet_aton(wanted, &wantedAddress))
	    isAddress=1;

	if(wanted)
	    wantedLen=strlen(wanted);

	net_if = MALLOC(net_if_t);
	if(net_if == NULL)
	    udpc_fatal(1, "Out of memory error");

#ifndef __MINGW32__

	s = socket(PF_INET, SOCK_DGRAM, 0);
	if (s < 0) {
	    perror("make socket");
	    exit(1);
	}	

	ifc.ifc_len = sizeof(ibuf);
	ifc.ifc_buf = (caddr_t) ibuf;

	if (ioctl(s, SIOCGIFCONF, (char *)&ifc) < 0 ||
            ifc.ifc_len < (signed int)sizeof(struct ifreq)) {
                perror("udpcast: SIOCGIFCONF: ");
                exit(1);
        }

	ifend = (struct ifreq *)((char *)ibuf + ifc.ifc_len);
	chosen=NULL;

	for (ifrp = ibuf ; ifrp < ifend;
#ifdef IFREQ_SIZE
	     ifrp = IFREQ_SIZE(*ifrp) + (char *)ifrp
#else
	     ifrp++
#endif       
	     ) {
	    unsigned long iaddr = getSinAddr(&ifrp->ifr_addr).s_addr;
	    int goodness;

	    if(ifrp->ifr_addr.sa_family != PF_INET)
		continue;
	    
	    if(wanted) {
		if(isAddress && iaddr == wantedAddress.s_addr) {
		    goodness=8;
		} else if(strcmp(wanted, ifrp->ifr_name) ==0) {
		    /* perfect match on interface name */
		    goodness=12;
		} else if(wanted != NULL && 
			  strncmp(wanted, ifrp->ifr_name, wantedLen) ==0) {
		    /* prefix match on interface name */
		    goodness=7;
		} else {
		    /* no match, try next */
		    continue;
		}
	    } else {
		if(iaddr == 0) {
		    /* disregard interfaces whose address is zero */
		    goodness = 1;
		} else if(iaddr == htonl(0x7f000001)) {
		    /* disregard localhost type devices */
		    goodness = 2;
		} else if(strcmp("eth0", ifrp->ifr_name) == 0 ||
			  strcmp("en0",  ifrp->ifr_name) == 0) {
		    /* prefer first ethernet interface */
		    goodness = 6;
		} else if(strncmp("eth0:", ifrp->ifr_name, 5) == 0) {
		    /* second choice: any secondary addresses of first ethernet */
		    goodness = 5;
		} else if(strncmp("eth", ifrp->ifr_name, 3) == 0 ||
			  strncmp("en",  ifrp->ifr_name, 2) == 0) {
		    /* and, if not available, any other ethernet device */
		    goodness = 4;
		} else {
		    goodness = 3;
		}
	    }

	    if(hasLink(s, ifrp->ifr_name))
	      /* Good or unknown link status privileged over known 
	       * disconnected */
	      goodness += 3;

	    /* If all else is the same, prefer interfaces that 
	     * have broadcast */
	    goodness = goodness * 2;
	    if(goodness >= lastGoodness) {
		/* Privilege broadcast-enabled interfaces */
		if(ioctl(s,  SIOCGIFBRDADDR, ifrp) < 0)
		    udpc_fatal(-1, "Error getting broadcast address for %s: %s\n",
			       ifrp->ifr_name, strerror(errno));
		if(getSinAddr(&ifrp->ifr_ifru.ifru_broadaddr).s_addr)
		    goodness++;
	    }

	    if(goodness > lastGoodness) {
		chosen = ifrp;
		lastGoodness = goodness;
		net_if->addr.s_addr = iaddr;
	    }
	}


	if(!chosen) {
	    fprintf(stderr, "No suitable network interface found\n");
	    fprintf(stderr, "The following interfaces are available:\n");

	    for (ifrp = ibuf ; ifrp < ifend;
#ifdef IFREQ_SIZE
		 ifrp = IFREQ_SIZE(*ifrp) + (char *)ifrp
#else
		 ifrp++
#endif
		 ) {
		char buffer[16];

		if(ifrp->ifr_addr.sa_family != PF_INET)
		    continue;

		fprintf(stderr, "\t%s\t%s\n",
			ifrp->ifr_name, 
			udpc_getIpString((struct sockaddr_in *)&ifrp->ifr_addr, buffer));
	    }
	    exit(1);
	}

	net_if->name = strdup(chosen->ifr_name);

#ifdef SIOCGIFINDEX
	/* Index for multicast subscriptions */
	if(ioctl(s,  SIOCGIFINDEX, chosen) < 0)
	    udpc_fatal(-1, "Error getting index for %s: %s\n", net_if->name,
		       strerror(errno));
	net_if->index = chosen->ifr_ifindex;
#endif

	/* Broadcast */
	if(ioctl(s,  SIOCGIFBRDADDR, chosen) < 0)
	    udpc_fatal(-1, "Error getting broadcast address for %s: %s\n",
		       net_if->name, strerror(errno));
	net_if->bcast = getSinAddr(&chosen->ifr_ifru.ifru_broadaddr);

	close(s);

#else /* __MINGW32__ */

	/* WINSOCK initialization */	
	wVersionRequested = MAKEWORD(2, 0); /* Request Winsock v2.0 */
	if (WSAStartup(wVersionRequested, &wsaData) != 0) /* Load Winsock DLL */ {
	    fprintf(stderr,"WSAStartup() failed");
	    exit(1);
	}
	/* End WINSOCK initialization */
	

	a=0;
	r=GetIpAddrTable(iptab, &a, TRUE);
	iptab=malloc(a);
	r=GetIpAddrTable(iptab, &a, TRUE);

	a=0;
	r=GetIfTable(iftab, &a, TRUE);
	iftab=malloc(a);
	r=GetIfTable(iftab, &a, TRUE);

	if(wanted && !strncmp(wanted, "eth", 3) && wanted[3]) {
	    char *ptr;
	    int n = strtoul(wanted+3, &ptr, 10);
	    if(!*ptr)
		wantedEtherNo=n;
	}

	for(i=0; i<iptab->dwNumEntries; i++) {
	    int goodness=-1;
	    unsigned long iaddr;
	    int isEther=0;
	    MIB_IFROW *ifrow;

	    iprow = &iptab->table[i];
	    iaddr = iprow->dwAddr;

	    ifrow = getIfRow(iftab, iprow->dwIndex);

	    if(ifrow && ifrow->dwPhysAddrLen == 6 && iprow->dwBCastAddr) {
		isEther=1;
		etherNo++;
	    }

	    if(wanted) {
		if(isAddress && iaddr == wantedAddress.s_addr) {
		    goodness=8;
		} else if(isEther && wantedEtherNo == etherNo) {
			goodness=9;
		} else if(ifrow->dwPhysAddrLen) {
		    int j;
		    const char *ptr=wanted;
		    for(j=0; *ptr && j<ifrow->dwPhysAddrLen; j++) {
			int digit = strtoul(ptr, (char**)&ptr, 16);
			if(digit != ifrow->bPhysAddr[j])
			    break; /* Digit mismatch */
			if(*ptr == '-' || *ptr == ':') {
			    ptr++;
			}
		    }
		    if(!*ptr && j == ifrow->dwPhysAddrLen) {
			goodness=9;
		    }
		}
	    } else {
		if(iaddr == 0) {
		    /* disregard interfaces whose address is zero */
		    goodness = 1;
		} else if(iaddr == htonl(0x7f000001)) {
		    /* disregard localhost type devices */
		    goodness = 2;
		} else if(isEther) {
		    /* prefer ethernet */
		    goodness = 6;
		} else if(ifrow->dwPhysAddrLen) {
		    /* then prefer interfaces which have a physical address */
		    goodness = 4;
		} else {
		    goodness = 3;
		}
	    }

	    goodness = goodness * 2;
	    /* If all else is the same, prefer interfaces that 
	     * have broadcast */
	    if(goodness >= lastGoodness) {
		/* Privilege broadcast-enabled interfaces */
		if(iprow->dwBCastAddr)
		    goodness++;
	    }

	    if(goodness > lastGoodness) {
		chosen = iprow;
		chosenIf = ifrow;
		lastGoodness = goodness;
	    }
	}
	
	if(!chosen) {
	    fprintf(stderr, "No suitable network interface found%s%s\n", 
		    wanted ? " for " : "", wanted ? wanted : "");
	    fprintf(stderr, "The following interfaces are available:\n");

	    for(i=0; i<iptab->dwNumEntries; i++) {
		char buffer[16];
		struct sockaddr_in addr;
		MIB_IFROW *ifrow;
		char *name=NULL;
		iprow = &iptab->table[i];
		addr.sin_addr.s_addr = iprow->dwAddr;
		ifrow = getIfRow(iftab, iprow->dwIndex);
		name = fmtName(ifrow);
		fprintf(stderr, " %15s  %s\n",
			udpc_getIpString(&addr, buffer),
			name ? name : "");
		if(name)
		    free(name);
	    }
	    exit(1);
	}

	net_if->bcast.s_addr = net_if->addr.s_addr = chosen->dwAddr;
	if(chosen->dwBCastAddr)
	    net_if->bcast.s_addr |= ~chosen->dwMask;
	if(chosenIf) {
	    net_if->name = fmtName(chosenIf);
	} else {
	    net_if->name = "*";
	}
	free(iftab);
	free(iptab);
#endif /* __MINGW32__ */

	return net_if;
}

/**
 * @param addr_type
 *   UCAST - my unicast address attached to this device
 *   BCAST - my broadcast addres attached to this device
 *   MCAST - multicast address
 * @param ifname
 *   Interface name
 * @param mcast
 *   Multicast address (only used if type MCAST)
 * @param port
 *   Port to bind address to
 */
int makeSocket(addr_type_t addr_type, 
	       net_if_t *net_if, 
	       struct sockaddr_in *tmpl,
	       int port) {
    int ret, s;
    struct sockaddr_in myaddr;
    in_addr_t ip=0;

#ifdef WINDOWS
    static int lastSocket=-1;
    /* Very ugly hack, but hey!, this is for Windows */

    if(addr_type == ADDR_TYPE_MCAST) {
	mcastListen(lastSocket, net_if, tmpl);
	return -1;
    } else if(addr_type != ADDR_TYPE_UCAST)
	return -1;
#endif

    s = socket(PF_INET, SOCK_DGRAM, 0);
    if (s < 0) {
	perror("make socket");
	exit(1);
    }

    if(addr_type == ADDR_TYPE_MCAST && tmpl != NULL) {
	ip = tmpl->sin_addr.s_addr;
    }

    ret = initSockAddress(addr_type, net_if, ip, port, &myaddr);
    if(ret < 0)
	udpc_fatal(1, "Could not get socket address fot %d/%s", 
		   addr_type, net_if->name);
    if(addr_type == ADDR_TYPE_BCAST && myaddr.sin_addr.s_addr == 0) {
      /* Attempting to bind to broadcast address on not-broadcast media ... */
      close(s);
      return -1;
    }
    ret = bind(s, (struct sockaddr *) &myaddr, sizeof(myaddr));
    if (ret < 0) {
	char buffer[16];
	udpc_fatal(1, "bind socket to %s:%d (%s)\n",
		   udpc_getIpString(&myaddr, buffer), 
		   udpc_getPort(&myaddr),
		   strerror(errno));
    }

    if(addr_type == ADDR_TYPE_MCAST)
	mcastListen(s, net_if, &myaddr);
#ifdef WINDOWS
    lastSocket=s;
#endif
    return s;
}

void printMyIp(net_if_t *net_if, int s)
{
    char buffer[16];
    struct sockaddr_in myaddr;

    getMyAddress(net_if, &myaddr);
    udpc_flprintf("%s", udpc_getIpString(&myaddr,buffer));
}

char *udpc_getIpString(struct sockaddr_in *addr, char *buffer) {
    long iaddr = htonl(getSinAddr(addr).s_addr);
    sprintf(buffer,"%ld.%ld.%ld.%ld", 
	    (iaddr >> 24) & 0xff,
	    (iaddr >> 16) & 0xff,
	    (iaddr >>  8) & 0xff,
	    iaddr & 0xff);
    return buffer;
}

int ipIsEqual(struct sockaddr_in *left, struct sockaddr_in *right) {
    return getSinAddr(left).s_addr == getSinAddr(right).s_addr;
}

int ipIsZero(struct sockaddr_in *ip) {
    return getSinAddr(ip).s_addr == 0;
}

unsigned short udpc_getPort(struct sockaddr_in *addr) {
    return ntohs(((struct sockaddr_in *) addr)->sin_port);
}

void setPort(struct sockaddr_in *addr, unsigned short port) {
    ((struct sockaddr_in *) addr)->sin_port = htons(port);
}


void clearIp(struct sockaddr_in *addr) {
    addr->sin_addr.s_addr = 0;
    addr->sin_family = AF_INET;
}

void setIpFromString(struct sockaddr_in *addr, char *ip) {
    safe_inet_aton(ip, &addr->sin_addr);
    addr->sin_family = AF_INET;
}

void copyIpFrom(struct sockaddr_in *dst, struct sockaddr_in *src) {
    dst->sin_addr = src->sin_addr;
    dst->sin_family = src->sin_family;
}

void getDefaultMcastAddress(net_if_t *net_if, struct sockaddr_in *mcast) {
    getMyAddress(net_if, mcast);
    mcast->sin_addr.s_addr &= htonl(0x07ffffff);
    mcast->sin_addr.s_addr |= htonl(0xe8000000);
}


void copyToMessage(unsigned char *dst, struct sockaddr_in *src) {    
    memcpy(dst, (char *) &((struct sockaddr_in *)src)->sin_addr,
	   sizeof(struct in_addr));
}


void copyFromMessage(struct sockaddr_in *dst, unsigned char *src) {
    memcpy((char *) &dst->sin_addr, src, sizeof(struct in_addr));
}

int isAddressEqual(struct sockaddr_in *a, struct sockaddr_in *b) {
    return !memcmp((char *) a, (char *)b, 8);
}

unsigned long parseSize(char *sizeString) {
    char *eptr;
    unsigned long size = strtoul(sizeString, &eptr, 10);
    if(eptr && *eptr) {
	switch(*eptr) {
	    case 'm':
	    case 'M':
		size *= 1024 * 1024;
		break;
	    case 'k':
	    case 'K':
		size *= 1024;
		break;
	    case '\0':
		break;
	    default:
		udpc_fatal(1, "Unit %c unsupported\n", *eptr);
	}
    }
    return size;
}


unsigned long parseSpeed(char *speedString) {
    char *eptr;
    unsigned long speed = strtoul(speedString, &eptr, 10);
    if(eptr && *eptr) {
	switch(*eptr) {
	    case 'm':
	    case 'M':
		speed *= 1000000;
		break;
	    case 'k':
	    case 'K':
		speed *= 1000;
		break;
	    case '\0':
		break;
	    default:
		udpc_fatal(1, "Unit %c unsupported\n", *eptr);
	}
    }
    return speed;
}

void zeroSockArray(int *socks, int nr) {
    int i;

    for(i=0; i<nr; i++)
	socks[i] = -1;
}

int selectSock(int *socks, int nr, int startTimeout) {
    fd_set read_set;
    int r;
    int maxFd;
    struct timeval tv, *tvp;
    if(startTimeout) {
	tv.tv_sec = startTimeout;
	tv.tv_usec = 0;
	tvp = &tv;
    } else {
	tvp = NULL;
    }
    maxFd = prepareForSelect(socks, nr, &read_set);
    r = select(maxFd+1, &read_set, NULL, NULL, tvp);
    if(r < 0)
	return r;
    return getSelectedSock(socks, nr, &read_set);
}

int prepareForSelect(int *socks, int nr, fd_set *read_set) {
    int i;
    int maxFd;
    FD_ZERO(read_set);
    maxFd=-1;
    for(i=0; i<nr; i++) {
	if(socks[i] == -1)
	    continue;
	FD_SET(socks[i], read_set);
	if(socks[i] > maxFd)
	    maxFd = socks[i];
    }
    return maxFd;
}

int getSelectedSock(int *socks, int nr, fd_set *read_set) {
    int i;
    int maxFd;
    maxFd=-1;
    for(i=0; i<nr; i++) {
	if(socks[i] == -1)
	    continue;
	if(FD_ISSET(socks[i], read_set))
	    return socks[i];
    }
    return -1;
}

void closeSock(int *socks, int nr, int target) {
    int i;
    int sock = socks[target];

    socks[target]=-1;
    for(i=0; i<nr; i++)
	if(socks[i] == sock)
	    return;
    close(sock);
}

int isMcastAddress(struct sockaddr_in *addr) {
    int ip = ntohl(addr->sin_addr.s_addr) >> 24;
    return ip >= 0xe0 && ip < 0xf0;
}


#ifdef __MINGW32__

static ssize_t getLength(const struct msghdr *msg) {
    ssize_t size=0;
    int i;

    for(i=0; i<msg->msg_iovlen; i++) {
	size += msg->msg_iov[i].iov_len;
    }
    return size;
}

static void doCopy(const struct msghdr *msg, char *ptr, int n, int dir) {
    int i;
    for(i=0; n >=0 && i<msg->msg_iovlen; i++) {
	int l = msg->msg_iov[i].iov_len;
	if(l > n)
	    l = n;   
	if(dir) {
	    memcpy(msg->msg_iov[i].iov_base, ptr, l);
	} else {
	    memcpy(ptr, msg->msg_iov[i].iov_base, l);
	}
	n   -= l;
	ptr += l;
    }
}

ssize_t recvmsg(int s, struct msghdr *msg, int flags) {
    ssize_t size=getLength(msg);
    char *buffer = malloc(size);
    int n; /* bytes left to copy */

    if(buffer == NULL) {
	/* Out of memory */
	errno = ENOMEM;
	return -1;
    }
    n = recvfrom(s, buffer, size, flags,
		 msg->msg_name, &msg->msg_namelen);
    doCopy(msg, buffer, n, 1);
    free(buffer);
    return n;
}

ssize_t sendmsg (int fd, const struct msghdr *msg, int flags) {
    ssize_t size=getLength(msg);
    char *buffer = malloc(size);
    int n;

    if(buffer == NULL) {
	/* Out of memory */
	errno = ENOMEM;
	return -1;
    }
    doCopy(msg, buffer, size, 0);
    n = sendto(fd, buffer, size, flags,
	       msg->msg_name, msg->msg_namelen);
    free(buffer);
    return n;
}

/* Gettimeofday function copied from http://www.daen.dk/archives/000384.html */
void gettimeofday(struct timeval* p, void* tz /* IGNORED */) {
     union {
       long long ns100; /*time since 1 Jan 1601 in 100ns units */
       FILETIME ft;
     } _now;

     GetSystemTimeAsFileTime( &(_now.ft) );
     p->tv_usec=(long)((_now.ns100 / 10LL) % 1000000LL );
     p->tv_sec= (long)((_now.ns100-(116444736000000000LL))/10000000LL);
     return;
   }

#endif /* __MINGW32__ */