1 files changed, 291 insertions, 0 deletions
diff --git a/lib/libc/net/linkaddr.c b/lib/libc/net/linkaddr.c
new file mode 100644
index 000000000000..5be4c0a7a43e
--- /dev/null
+++ b/lib/libc/net/linkaddr.c
@@ -0,0 +1,291 @@
+/*-
+ * SPDX-License-Identifier: BSD-3-Clause
+ *
+ * Copyright (c) 1990, 1993
+ *	The Regents of the University of California.  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.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 3. Neither the name of the University nor the names of its contributors
+ *    may be used to endorse or promote products derived from this software
+ *    without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``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 THE REGENTS OR CONTRIBUTORS 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.
+ */
+
+#include <sys/types.h>
+#include <sys/socket.h>
+
+#include <net/if.h>
+#include <net/if_dl.h>
+
+#include <assert.h>
+#include <errno.h>
+#include <stdint.h>
+#include <string.h>
+
+int
+link_addr(const char *addr, struct sockaddr_dl *sdl)
+{
+	char *cp = sdl->sdl_data;
+	char *cplim = sdl->sdl_len + (char *)sdl;
+	const char *nptr;
+	size_t newsize;
+	int error = 0;
+	char delim = 0;
+
+	/* Initialise the sdl to zero, except for sdl_len. */
+	bzero((char *)&sdl->sdl_family, sdl->sdl_len - 1);
+	sdl->sdl_family = AF_LINK;
+
+	/*
+	 * Everything up to the first ':' is the interface name.  Usually the
+	 * ':' should always be present even if there's no interface name, but
+	 * since this interface was poorly specified in the past, accept a
+	 * missing colon as meaning no interface name.
+	 */
+	if ((nptr = strchr(addr, ':')) != NULL) {
+		size_t namelen = nptr - addr;
+
+		/* Ensure the sdl is large enough to store the name. */
+		if (namelen > cplim - cp) {
+			errno = ENOSPC;
+			return (-1);
+		}
+
+		memcpy(cp, addr, namelen);
+		cp += namelen;
+		sdl->sdl_nlen = namelen;
+		/* Skip the interface name and the colon. */
+		addr += namelen + 1;
+	}
+
+	/*
+	 * The remainder of the string should be hex digits representing the
+	 * address, with optional delimiters.  Each two hex digits form one
+	 * octet, but octet output can be forced using a delimiter, so we accept
+	 * a long string of hex digits, or a mix of delimited and undelimited
+	 * digits like "1122.3344.5566", or delimited one- or two-digit octets
+	 * like "1.22.3".
+	 *
+	 * If anything fails at this point, exit the loop so we set sdl_alen and
+	 * sdl_len based on whatever we did manage to parse.  This preserves
+	 * compatibility with the 4.3BSD version of link_addr, which had no way
+	 * to indicate an error and would just return.
+	 */
+#define DIGIT(c)						\
+	 (((c) >= '0' && (c) <= '9') ? ((c) - '0')		\
+	: ((c) >= 'a' && (c) <= 'f') ? ((c) - 'a' + 10)		\
+	: ((c) >= 'A' && (c) <= 'F') ? ((c) - 'A' + 10)		\
+	: (-1))
+#define ISDELIM(c) (((c) == '.' || (c) == ':' || (c) == '-') && \
+    (delim == 0 || delim == (c)))
+
+	for (;;) {
+		int digit, digit2;
+
+		/*
+		 * Treat any leading delimiters as empty bytes.  This supports
+		 * the (somewhat obsolete) form of Ethernet addresses with empty
+		 * octets, e.g. "1::3:4:5:6".
+		 */
+		while (ISDELIM(*addr) && cp < cplim) {
+			delim = *addr++;
+			*cp++ = 0;
+		}
+
+		/* Did we reach the end of the string? */
+		if (*addr == '\0')
+			break;
+
+		/*
+		 * If not, the next character must be a digit, so make sure we
+		 * have room for at least one more octet.
+		 */
+
+		if (cp >= cplim) {
+			error = ENOSPC;
+			break;
+		}
+
+		if ((digit = DIGIT(*addr)) == -1) {
+			error = EINVAL;
+			break;
+		}
+
+		++addr;
+
+		/* If the next character is another digit, consume it. */
+		if ((digit2 = DIGIT(*addr)) != -1) {
+			digit = (digit << 4) | digit2;
+			++addr;
+		}
+
+		if (ISDELIM(*addr)) {
+			/*
+			 * If the digit is followed by a delimiter, write it
+			 * and consume the delimiter.
+			 */
+			delim = *addr++;
+			*cp++ = digit;
+		} else if (DIGIT(*addr) != -1) {
+			/*
+			 * If two digits are followed by a third digit, treat
+			 * the two digits we have as a single octet and
+			 * continue.
+			 */
+			*cp++ = digit;
+		} else if (*addr == '\0') {
+			/* If the digit is followed by EOS, we're done. */
+			*cp++ = digit;
+			break;
+		} else {
+			/* Otherwise, the input was invalid. */
+			error = EINVAL;
+			break;
+		}
+	}
+#undef DIGIT
+#undef ISDELIM
+
+	/* How many bytes did we write to the address? */
+	sdl->sdl_alen = cp - LLADDR(sdl);
+
+	/*
+	 * The user might have given us an sdl which is larger than sizeof(sdl);
+	 * in that case, record the actual size of the new sdl.
+	 */
+	newsize = cp - (char *)sdl;
+	if (newsize > sizeof(*sdl))
+		sdl->sdl_len = (u_char)newsize;
+
+	if (error == 0)
+		return (0);
+
+	errno = error;
+	return (-1);
+}
+
+
+char *
+link_ntoa(const struct sockaddr_dl *sdl)
+{
+	static char obuf[64];
+	size_t buflen;
+	_Static_assert(sizeof(obuf) >= IFNAMSIZ + 20, "obuf is too small");
+
+	/*
+	 * Ignoring the return value of link_ntoa_r() is safe here because it
+	 * always writes the terminating NUL.  This preserves the traditional
+	 * behaviour of link_ntoa().
+	 */
+	buflen = sizeof(obuf);
+	(void)link_ntoa_r(sdl, obuf, &buflen);
+	return obuf;
+}
+
+int
+link_ntoa_r(const struct sockaddr_dl *sdl, char *obuf, size_t *buflen)
+{
+	static const char hexlist[] = "0123456789abcdef";
+	char *out;
+	const u_char *in, *inlim;
+	int namelen, i, rem;
+	size_t needed;
+
+	assert(sdl);
+	assert(buflen);
+	/* obuf may be null */
+
+	needed = 1; /* 1 for the NUL */
+	out = obuf;
+	if (obuf)
+		rem = *buflen;
+	else
+		rem = 0;
+
+/*
+ * Check if at least n bytes are available in the output buffer, plus 1 for the
+ * trailing NUL.  If not, set rem = 0 so we stop writing.
+ * Either way, increment needed by the amount we would have written.
+ */
+#define CHECK(n) do {				\
+		if ((SIZE_MAX - (n)) >= needed)	\
+			needed += (n);		\
+		if (rem >= ((n) + 1))		\
+			rem -= (n);		\
+		else				\
+			rem = 0;		\
+	} while (0)
+
+/*
+ * Write the char c to the output buffer, unless the buffer is full.
+ * Note that if obuf is NULL, rem is always zero.
+ */
+#define OUT(c) do {			\
+		if (rem > 0)		\
+			*out++ = (c);	\
+	} while (0)
+
+	namelen = (sdl->sdl_nlen <= IFNAMSIZ) ? sdl->sdl_nlen : IFNAMSIZ;
+	if (namelen > 0) {
+		CHECK(namelen);
+		if (rem > 0) {
+			bcopy(sdl->sdl_data, out, namelen);
+			out += namelen;
+		}
+
+		if (sdl->sdl_alen > 0) {
+			CHECK(1);
+			OUT(':');
+		}
+	}
+
+	in = (const u_char *)LLADDR(sdl);
+	inlim = in + sdl->sdl_alen;
+
+	while (in < inlim) {
+		if (in != (const u_char *)LLADDR(sdl)) {
+			CHECK(1);
+			OUT('.');
+		}
+		i = *in++;
+		if (i > 0xf) {
+			CHECK(2);
+			OUT(hexlist[i >> 4]);
+			OUT(hexlist[i & 0xf]);
+		} else {
+			CHECK(1);
+			OUT(hexlist[i]);
+		}
+	}
+
+#undef CHECK
+#undef OUT
+
+	/*
+	 * We always leave enough room for the NUL if possible, but the user
+	 * might have passed a NULL or zero-length buffer.
+	 */
+	if (out && *buflen)
+		*out = '\0';
+
+	*buflen = needed;
+	return ((rem > 0) ? 0 : -1);
+}