/*- * 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); }
