Index: head/lib/libc/net/ether_addr.c =================================================================== --- head/lib/libc/net/ether_addr.c (revision 169521) +++ head/lib/libc/net/ether_addr.c (revision 169522) @@ -1,215 +1,230 @@ /* * Copyright (c) 1995 Bill Paul . + * Copyright (c) 2007 Robert N. M. Watson * 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. All advertising materials mentioning features or use of this software * must display the following acknowledgement: * This product includes software developed by Bill Paul. * 4. Neither the name of the author nor the names of any co-contributors * may be used to endorse or promote products derived from this software * without specific prior written permission. * * THIS SOFTWARE IS PROVIDED BY Bill Paul 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. * * ethernet address conversion and lookup routines * * Written by Bill Paul * Center for Telecommunications Research * Columbia University, New York City */ #include __FBSDID("$FreeBSD$"); #include #include #include #include #ifdef YP #include #include #include #endif #include #include #include #include #ifndef _PATH_ETHERS #define _PATH_ETHERS "/etc/ethers" #endif /* * Parse a string of text containing an ethernet address and hostname and * separate it into its component parts. */ int ether_line(const char *l, struct ether_addr *e, char *hostname) { - int i, o[6]; + int i, o[6]; - i = sscanf(l, "%x:%x:%x:%x:%x:%x %s", &o[0], &o[1], &o[2], &o[3], + i = sscanf(l, "%x:%x:%x:%x:%x:%x %s", &o[0], &o[1], &o[2], &o[3], &o[4], &o[5], hostname); if (i != 7) - return (i); - for (i=0; i<6; i++) - e->octet[i] = o[i]; - return (0); + return (i); + for (i=0; i<6; i++) + e->octet[i] = o[i]; + return (0); } /* * Convert an ASCII representation of an ethernet address to binary form. */ struct ether_addr * -ether_aton(const char *a) +ether_aton_r(const char *a, struct ether_addr *e) { - int i; - static struct ether_addr o; + int i; unsigned int o0, o1, o2, o3, o4, o5; - i = sscanf(a, "%x:%x:%x:%x:%x:%x", &o0, &o1, &o2, &o3, &o4, &o5); - if (i != 6) - return (NULL); - o.octet[0]=o0; - o.octet[1]=o1; - o.octet[2]=o2; - o.octet[3]=o3; - o.octet[4]=o4; - o.octet[5]=o5; - return ((struct ether_addr *)&o); + i = sscanf(a, "%x:%x:%x:%x:%x:%x", &o0, &o1, &o2, &o3, &o4, &o5); + if (i != 6) + return (NULL); + e->octet[0]=o0; + e->octet[1]=o1; + e->octet[2]=o2; + e->octet[3]=o3; + e->octet[4]=o4; + e->octet[5]=o5; + return (e); } +struct ether_addr * +ether_aton(const char *a) +{ + static struct ether_addr e; + + return (ether_aton_r(a, &e)); +} + /* * Convert a binary representation of an ethernet address to an ASCII string. */ char * +ether_ntoa_r(const struct ether_addr *n, char *a) +{ + int i; + + i = sprintf(a, "%02x:%02x:%02x:%02x:%02x:%02x", n->octet[0], + n->octet[1], n->octet[2], n->octet[3], n->octet[4], n->octet[5]); + if (i < 17) + return (NULL); + return (a); +} + +char * ether_ntoa(const struct ether_addr *n) { - int i; static char a[18]; - i = sprintf(a, "%02x:%02x:%02x:%02x:%02x:%02x", n->octet[0], - n->octet[1], n->octet[2], n->octet[3], n->octet[4], n->octet[5]); - if (i < 17) - return (NULL); - return ((char *)&a); + return (ether_ntoa_r(n, a)); } /* * Map an ethernet address to a hostname. Use either /etc/ethers or NIS/YP. */ int ether_ntohost(char *hostname, const struct ether_addr *e) { FILE *fp; char buf[BUFSIZ + 2]; struct ether_addr local_ether; char local_host[MAXHOSTNAMELEN]; #ifdef YP char *result; int resultlen; char *ether_a; char *yp_domain; #endif if ((fp = fopen(_PATH_ETHERS, "r")) == NULL) return (1); while (fgets(buf,BUFSIZ,fp)) { if (buf[0] == '#') continue; #ifdef YP if (buf[0] == '+') { if (yp_get_default_domain(&yp_domain)) continue; ether_a = ether_ntoa(e); if (yp_match(yp_domain, "ethers.byaddr", ether_a, strlen(ether_a), &result, &resultlen)) { continue; } strncpy(buf, result, resultlen); buf[resultlen] = '\0'; free(result); } #endif if (!ether_line(buf, &local_ether, local_host)) { if (!bcmp((char *)&local_ether.octet[0], (char *)&e->octet[0], 6)) { /* We have a match. */ strcpy(hostname, local_host); fclose(fp); return(0); } } } fclose(fp); return (1); } /* * Map a hostname to an ethernet address using /etc/ethers or NIS/YP. */ int ether_hostton(const char *hostname, struct ether_addr *e) { FILE *fp; char buf[BUFSIZ + 2]; struct ether_addr local_ether; char local_host[MAXHOSTNAMELEN]; #ifdef YP char *result; int resultlen; char *yp_domain; #endif if ((fp = fopen(_PATH_ETHERS, "r")) == NULL) return (1); while (fgets(buf,BUFSIZ,fp)) { if (buf[0] == '#') continue; #ifdef YP if (buf[0] == '+') { if (yp_get_default_domain(&yp_domain)) continue; if (yp_match(yp_domain, "ethers.byname", hostname, strlen(hostname), &result, &resultlen)) { continue; } strncpy(buf, result, resultlen); buf[resultlen] = '\0'; free(result); } #endif if (!ether_line(buf, &local_ether, local_host)) { if (!strcmp(hostname, local_host)) { /* We have a match. */ bcopy((char *)&local_ether.octet[0], (char *)&e->octet[0], 6); fclose(fp); return(0); } } } fclose(fp); return (1); } Index: head/lib/libc/net/ethers.3 =================================================================== --- head/lib/libc/net/ethers.3 (revision 169521) +++ head/lib/libc/net/ethers.3 (revision 169522) @@ -1,201 +1,234 @@ -.\" Copyright (c) 1995 -.\" Bill Paul . All rights reserved. +.\" Copyright (c) 1995 Bill Paul . +.\" Copyright (c) 2007 Robert N. M. Watson +.\" 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. All advertising materials mentioning features or use of this software .\" must display the following acknowledgement: .\" This product includes software developed by Bill Paul. .\" 4. Neither the name of the author nor the names of any co-contributors .\" may be used to endorse or promote products derived from this software .\" without specific prior written permission. .\" .\" THIS SOFTWARE IS PROVIDED BY Bill Paul 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. .\" .\" $FreeBSD$ .\" -.Dd April 12, 1995 +.Dd May 13, 2007 .Dt ETHERS 3 .Os .Sh NAME .Nm ethers , .Nm ether_line , .Nm ether_aton , +.Nm ether_aton_r , .Nm ether_ntoa , +.Nm ether_ntoa_r , .Nm ether_ntohost , .Nm ether_hostton .Nd Ethernet address conversion and lookup routines .Sh LIBRARY .Lb libc .Sh SYNOPSIS .In sys/types.h .In sys/socket.h .In net/ethernet.h .Ft int .Fn ether_line "const char *l" "struct ether_addr *e" "char *hostname" .Ft struct ether_addr * .Fn ether_aton "const char *a" +.Ft struct ether_addr * +.Fn ether_aton_r "const char *a" "struct ether_addr *e" .Ft char * .Fn ether_ntoa "const struct ether_addr *n" +.Ft char * +.Fn ether_ntoa_r "const struct ether_addr *n" "char *buf" .Ft int .Fn ether_ntohost "char *hostname" "const struct ether_addr *e" .Ft int .Fn ether_hostton "const char *hostname" "struct ether_addr *e" .Sh DESCRIPTION These functions operate on ethernet addresses using an .Vt ether_addr structure, which is defined in the header file .In netinet/if_ether.h : .Bd -literal -offset indent /* * The number of bytes in an ethernet (MAC) address. */ #define ETHER_ADDR_LEN 6 /* * Structure of a 48-bit Ethernet address. */ struct ether_addr { u_char octet[ETHER_ADDR_LEN]; }; .Ed .Pp The function .Fn ether_line scans .Fa l , an .Tn ASCII string in .Xr ethers 5 format and sets .Fa e to the ethernet address specified in the string and .Fa h to the hostname. This function is used to parse lines from .Pa /etc/ethers into their component parts. .Pp The .Fn ether_aton -function converts an +and +.Fn ether_aton_r +functions convert .Tn ASCII -representation of an ethernet address into an +representation of ethernet addresses into .Vt ether_addr -structure. -Likewise, +structures. +Likewise, the .Fn ether_ntoa -converts an ethernet address specified as an +and +.Fn ether_ntoa_r +functions +convert ethernet addresses specified as .Vt ether_addr -structure into an +structures into .Tn ASCII -string. +strings. .Pp The .Fn ether_ntohost and .Fn ether_hostton functions map ethernet addresses to their corresponding hostnames as specified in the .Pa /etc/ethers database. The .Fn ether_ntohost function converts from ethernet address to hostname, and .Fn ether_hostton converts from hostname to ethernet address. .Sh RETURN VALUES The .Fn ether_line function returns zero on success and non-zero if it was unable to parse any part of the supplied line .Fa l . It returns the extracted ethernet address in the supplied .Vt ether_addr structure .Fa e and the hostname in the supplied string .Fa h . .Pp On success, .Fn ether_ntoa -returns a pointer to a string containing an +and +.Fn ether_ntoa_r +functions return a pointer to a string containing an .Tn ASCII representation of an ethernet address. If it is unable to convert the supplied .Vt ether_addr structure, it returns a .Dv NULL pointer. +.Fn ether_ntoa +stores the result in a static buffer; +.Fn ether_ntoa_r +stores the result in a user-passed buffer. +.Pp + Likewise, .Fn ether_aton -returns a pointer to an +and +.Fn ether_aton_r +return a pointer to an .Vt ether_addr structure on success and a .Dv NULL pointer on failure. +.Fn ether_aton +stores the result in a static buffer; +.Fn ether_aton_r +stores the result in a user-passed buffer. .Pp The .Fn ether_ntohost and .Fn ether_hostton functions both return zero on success or non-zero if they were unable to find a match in the .Pa /etc/ethers database. .Sh NOTES The user must insure that the hostname strings passed to the .Fn ether_line , .Fn ether_ntohost and .Fn ether_hostton functions are large enough to contain the returned hostnames. .Sh NIS INTERACTION If the .Pa /etc/ethers contains a line with a single + in it, the .Fn ether_ntohost and .Fn ether_hostton functions will attempt to consult the NIS .Pa ethers.byname and .Pa ethers.byaddr maps in addition to the data in the .Pa /etc/ethers file. .Sh SEE ALSO .Xr ethers 5 , .Xr yp 8 .Sh HISTORY This particular implementation of the .Nm library functions were written for and first appeared in .Fx 2.1 . +Thread-safe function variants first appeared in +.Fx 7.0 . .Sh BUGS The .Fn ether_aton and .Fn ether_ntoa functions returns values that are stored in static memory areas which may be overwritten the next time they are called. +.Pp +.Fn ether_ntoa_r +accepts a character buffer pointer, but not a buffer length. +The caller must ensure adequate space is available in the buffer in order to +avoid a buffer overflow.