[RFC] get/freeifaddrs implementation ported from newlib

[RFC] get/freeifaddrs implementation ported from newlib

[Isaac Dunham]

[-- Attachment #1: Type: text/plain, Size: 722 bytes --]

Hello,
Here's a patch with getifaddrs & freeifaddrs.
I don't consider it ready to push yet, but would like comments/improvements.
The header is my own work, public domain; the C source is BSDi which is essentially the same as MIT.
I based it on the newlib 1.16.0 version, with the macros removed.
(newlib later removed getifaddrs either because it was not used or because it conditionally included a header with 4-clause BSD license; the code including that header has been removed).

Testing: I could only test on i386 with ipv4; there's a note suggesting that inet4 on LP64 (for us, x86_64) may be broken. ipv6 should also be tested.

The test is copy-pasted from getifaddrs(3).

HTH,
Isaac Dunham <idunham@lavabit.com>

[-- Attachment #2: ifaddr.diff --]
[-- Type: text/x-diff, Size: 5006 bytes --]

diff --git a/include/ifaddrs.h b/include/ifaddrs.h
new file mode 100644
index 0000000..342d4bd
--- /dev/null
+++ b/include/ifaddrs.h
@@ -0,0 +1,31 @@
+#ifndef _IFADDRS_H
+#define _IFADDRS_H 1
+
+struct ifaddrs {
+	struct ifaddrs	*ifa_next;
+	char		*ifa_name;
+	unsigned int	 ifa_flags;
+	struct sockaddr	*ifa_addr;
+	struct sockaddr	*ifa_netmask;
+	union {
+		struct sockaddr *ifu_broadaddr;
+		struct sockaddr *ifu_dstaddr;
+	} ifa_ifu;
+	#define	ifa_broadaddr ifa_ifu.ifu_broadaddr
+	#define	ifa_dstaddr   ifa_ifu.ifu_dstaddr
+	void		*ifa_data;
+};
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+int getifaddrs(struct ifaddrs **);
+
+void freeifaddrs(struct ifaddrs *);
+
+#ifdef __cpluplus
+}
+#endif
+
+#endif
diff --git a/src/network/getifaddrs.c b/src/network/getifaddrs.c
new file mode 100644
index 0000000..57920bb
--- /dev/null
+++ b/src/network/getifaddrs.c
@@ -0,0 +1,163 @@
+/*
+ * Copyright (c) 1995, 1999
+ *	Berkeley Software Design, Inc.  All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ *
+ * THIS SOFTWARE IS PROVIDED BY Berkeley Software Design, Inc. ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL Berkeley Software Design, Inc. BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ *
+ *	BSDI getifaddrs.c,v 2.12 2000/02/23 14:51:59 dab Exp
+ */
+/*
+ * NOTE: SIOCGIFCONF case is not LP64 friendly.  it also does not perform
+ * try-and-error for region size.
+ */
+
+#define _BSD_SOURCE
+#include <sys/types.h>
+#include <sys/types.h>
+#include <unistd.h>
+
+#include <sys/types.h>
+#include <sys/ioctl.h>
+#include <sys/socket.h>
+#include <net/if.h>
+
+#include <ifaddrs.h>
+#include <stdlib.h>
+#include <string.h>
+
+#if !defined(AF_LINK)
+#define	SA_LEN(sa)	sizeof(struct sockaddr)
+#endif
+
+#if !defined(SA_LEN)
+#define	SA_LEN(sa)	sizeof(struct sockaddr)
+#endif
+
+#define	SALIGN	(sizeof(long) - 1)
+#define	SA_RLEN(sa)	(sizeof(struct sockaddr) ? ((sizeof(struct sockaddr) + SALIGN) & ~SALIGN) : (SALIGN + 1))
+
+#ifndef	ALIGNBYTES
+/*
+ * On systems with a routing socket, ALIGNBYTES should match the value
+ * that the kernel uses when building the messages.
+ */
+#define	ALIGNBYTES	XXX
+#endif
+#ifndef	ALIGN
+#define	ALIGN(p)	(((u_long)(p) + ALIGNBYTES) &~ ALIGNBYTES)
+#endif
+
+int
+getifaddrs(struct ifaddrs **pif)
+{
+	int icnt = 1;
+	int dcnt = 0;
+	int ncnt = 0;
+	struct ifaddrs *ifa, *ift;
+	char buf[1024];
+	int m, sock;
+	struct ifconf ifc;
+	struct ifreq *ifr;
+	struct ifreq *lifr;
+	int i;
+	size_t len, alen;
+	char *data;
+	char *names;
+
+	ifc.ifc_buf = buf;
+	ifc.ifc_len = sizeof(buf);
+
+	if ((sock = socket(AF_INET, SOCK_STREAM, 0)) < 0)
+		return (-1);
+	i =  ioctl(sock, SIOCGIFCONF, (char *)&ifc);
+	close(sock);
+	if (i < 0)
+		return (-1);
+
+	ifr = ifc.ifc_req;
+	lifr = (struct ifreq *)&ifc.ifc_buf[ifc.ifc_len];
+
+	while (ifr < lifr) {
+		struct sockaddr *sa;
+
+		sa = &ifr->ifr_addr;
+		++icnt;
+		dcnt += SA_RLEN(sa);
+		ncnt += sizeof(ifr->ifr_name) + 1;
+		
+		if (SA_LEN(sa) < sizeof(*sa))
+			ifr = (struct ifreq *)(((char *)sa) + sizeof(*sa));
+		else
+			ifr = (struct ifreq *)(((char *)sa) + SA_LEN(sa));
+	}
+
+	if (icnt + dcnt + ncnt == 1) {
+		*pif = NULL;
+		free(buf);
+		return (0);
+	}
+	data = malloc(sizeof(struct ifaddrs) * icnt + dcnt + ncnt);
+	if (data == NULL) {
+		free(buf);
+		return(-1);
+	}
+
+	ifa = (struct ifaddrs *)(void *)data;
+	data += sizeof(struct ifaddrs) * icnt;
+	names = data + dcnt;
+
+	memset(ifa, 0, sizeof(struct ifaddrs) * icnt);
+	ift = ifa;
+
+	ifr = ifc.ifc_req;
+	lifr = (struct ifreq *)&ifc.ifc_buf[ifc.ifc_len];
+
+	while (ifr < lifr) {
+		struct sockaddr *sa;
+
+		ift->ifa_name = names;
+		names[sizeof(ifr->ifr_name)] = 0;
+		strncpy(names, ifr->ifr_name, sizeof(ifr->ifr_name));
+		while (*names++)
+			;
+
+		ift->ifa_addr = (struct sockaddr *)data;
+		sa = &ifr->ifr_addr;
+		memcpy(data, sa, SA_LEN(sa));
+		data += SA_RLEN(sa);
+		
+		ifr = (struct ifreq *)(((char *)sa) + SA_LEN(sa));
+		ift = (ift->ifa_next = ift + 1);
+	}
+	if (--ift >= ifa) {
+		ift->ifa_next = NULL;
+		*pif = ifa;
+	} else {
+		*pif = NULL;
+		free(ifa);
+	}
+	return (0);
+}
+
+void
+freeifaddrs(struct ifaddrs *ifp)
+{
+
+	free(ifp);
+}

[-- Attachment #3: ifaddr-test.c --]
[-- Type: text/x-csrc, Size: 1583 bytes --]


#include <arpa/inet.h>
#include <sys/socket.h>
#include <netdb.h>
#include <ifaddrs.h>
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>

int main(int argc, char *argv[])
{
    struct ifaddrs *ifaddr, *ifa;
    int family, s;
    char host[NI_MAXHOST];

    if (getifaddrs(&ifaddr) == -1) {
        perror("getifaddrs");
        exit(EXIT_FAILURE);
    }

    /* Walk through linked list, maintaining head pointer so we
       can free list later */

    for (ifa = ifaddr; ifa != NULL; ifa = ifa->ifa_next) {
        family = ifa->ifa_addr->sa_family;

        /* Display interface name and family (including symbolic
           form of the latter for the common families) */

        printf("%s  address family: %d%s\n",
                ifa->ifa_name, family,
                (family == AF_PACKET) ? " (AF_PACKET)" :
                (family == AF_INET) ?   " (AF_INET)" :
                (family == AF_INET6) ?  " (AF_INET6)" : "");

        /* For an AF_INET* interface address, display the address */

        if (family == AF_INET || family == AF_INET6) {
            s = getnameinfo(ifa->ifa_addr,
                    (family == AF_INET) ? sizeof(struct sockaddr_in) :
                                          sizeof(struct sockaddr_in6),
                    host, NI_MAXHOST, NULL, 0, NI_NUMERICHOST);
            if (s != 0) {
                printf("getnameinfo() failed: %s\n", gai_strerror(s));
                exit(EXIT_FAILURE);
            }
            printf("\taddress: <%s>\n", host);
        }
    }

    freeifaddrs(ifaddr);
    exit(EXIT_SUCCESS);
}