Rearrange bootpd

1 files changed, 145 insertions, 0 deletions

diff --git a/libexec/bootpd/getif.c b/libexec/bootpd/getif.c
new file mode 100644
index 0000000..6cc1649
--- /dev/null
+++ b/libexec/bootpd/getif.c
@@ -0,0 +1,145 @@
+/*
+ * getif.c : get an interface structure
+ */
+
+#include <sys/types.h>
+#include <sys/socket.h>
+#include <sys/ioctl.h>
+
+#if defined(SUNOS) || defined(SVR4)
+#include <sys/sockio.h>
+#endif
+#ifdef	SVR4
+#include <sys/stropts.h>
+#endif
+
+#include <net/if.h>				/* for struct ifreq */
+#include <netinet/in.h>
+
+#ifndef	NO_UNISTD
+#include <unistd.h>
+#endif
+#include <syslog.h>
+#include <errno.h>
+#include <assert.h>
+
+#include "getif.h"
+#include "report.h"
+
+#ifdef	__bsdi__
+#define BSD 43
+#endif
+
+static struct ifreq ifreq[10];	/* Holds interface configuration */
+static struct ifconf ifconf;	/* points to ifreq */
+
+static int nmatch();
+
+/* Return a pointer to the interface struct for the passed address. */
+struct ifreq *
+getif(s, addrp)
+	int s;						/* socket file descriptor */
+	struct in_addr *addrp;		/* destination address on interface */
+{
+	int maxmatch;
+	int len, m, incr;
+	struct ifreq *ifrq, *ifrmax;
+	struct sockaddr_in *sip;
+	char *p;
+
+	/* If no address was supplied, just return NULL. */
+	if (!addrp)
+		return (struct ifreq *) 0;
+
+	/* Get the interface config if not done already. */
+	if (ifconf.ifc_len == 0) {
+#ifdef	SVR4
+		/*
+		 * SysVr4 returns garbage if you do this the obvious way!
+		 * This one took a while to figure out... -gwr
+		 */
+		struct strioctl ioc;
+		ioc.ic_cmd = SIOCGIFCONF;
+		ioc.ic_timout = 0;
+		ioc.ic_len = sizeof(ifreq);
+		ioc.ic_dp = (char *) ifreq;
+		m = ioctl(s, I_STR, (char *) &ioc);
+		ifconf.ifc_len = ioc.ic_len;
+		ifconf.ifc_req = ifreq;
+#else	/* SVR4 */
+		ifconf.ifc_len = sizeof(ifreq);
+		ifconf.ifc_req = ifreq;
+		m = ioctl(s, SIOCGIFCONF, (caddr_t) & ifconf);
+#endif	/* SVR4 */
+		if ((m < 0) || (ifconf.ifc_len <= 0)) {
+			report(LOG_ERR, "ioctl SIOCGIFCONF");
+			return (struct ifreq *) 0;
+		}
+	}
+	maxmatch = 7;				/* this many bits or less... */
+	ifrmax = (struct ifreq *) 0;/* ... is not a valid match  */
+	p = (char *) ifreq;
+	len = ifconf.ifc_len;
+	while (len > 0) {
+		ifrq = (struct ifreq *) p;
+		sip = (struct sockaddr_in *) &ifrq->ifr_addr;
+		m = nmatch(addrp, &(sip->sin_addr));
+		if (m > maxmatch) {
+			maxmatch = m;
+			ifrmax = ifrq;
+		}
+		/* XXX - Could this be just #ifndef IFNAMSIZ instead? -gwr */
+#if (BSD - 0) < 43
+		/* BSD not defined or earlier than 4.3 */
+		incr = sizeof(*ifrq);
+#else /* NetBSD */
+		incr = ifrq->ifr_addr.sa_len + IFNAMSIZ;
+#endif /* NetBSD */
+
+		p += incr;
+		len -= incr;
+	}
+
+	return ifrmax;
+}
+
+/*
+ * Return the number of leading bits matching in the
+ * internet addresses supplied.
+ */
+static int
+nmatch(ca, cb)
+	u_char *ca, *cb;			/* ptrs to IP address, network order */
+{
+	u_int m = 0;				/* count of matching bits */
+	u_int n = 4;				/* bytes left, then bitmask */
+
+	/* Count matching bytes. */
+	while (n && (*ca == *cb)) {
+		ca++;
+		cb++;
+		m += 8;
+		n--;
+	}
+	/* Now count matching bits. */
+	if (n) {
+		n = 0x80;
+		while (n && ((*ca & n) == (*cb & n))) {
+			m++;
+			n >>= 1;
+		}
+	}
+	return (m);
+}
+
+/*
+ * Local Variables:
+ * tab-width: 4
+ * c-indent-level: 4
+ * c-argdecl-indent: 4
+ * c-continued-statement-offset: 4
+ * c-continued-brace-offset: -4
+ * c-label-offset: -4
+ * c-brace-offset: 0
+ * End:
+ */