diff options
Diffstat (limited to 'src/util/inet_proto.c')
| -rw-r--r-- | src/util/inet_proto.c | 328 |
1 files changed, 328 insertions, 0 deletions
diff --git a/src/util/inet_proto.c b/src/util/inet_proto.c new file mode 100644 index 0000000..fedf761 --- /dev/null +++ b/src/util/inet_proto.c @@ -0,0 +1,328 @@ +/*++ +/* NAME +/* inet_proto 3 +/* SUMMARY +/* convert protocol names to assorted constants +/* SYNOPSIS +/* #include <inet_proto.h> +/* +/* typedef struct { +/* .in +4 +/* unsigned ai_family; /* PF_UNSPEC, PF_INET, or PF_INET6 */ +/* unsigned *ai_family_list; /* PF_INET and/or PF_INET6 */ +/* unsigned *dns_atype_list;/* TAAAA and/or TA */ +/* unsigned char *sa_family_list;/* AF_INET6 and/or AF_INET */ +/* .in -4 +/* } INET_PROTO_INFO; +/* +/* const INET_PROTO_INFO *inet_proto_init(context, protocols) +/* +/* const INET_PROTO_INFO *inet_proto_info() +/* DESCRIPTION +/* inet_proto_init() converts a string with protocol names +/* into null-terminated lists of appropriate constants used +/* by Postfix library routines. The idea is that one should +/* be able to configure an MTA for IPv4 only, without having +/* to recompile code (what a concept). +/* +/* Unfortunately, some compilers won't link initialized data +/* without a function call into the same source module, so +/* we invoke inet_proto_info() in order to access the result +/* from inet_proto_init() from within library routines. +/* inet_proto_info() also conveniently initializes the data +/* to built-in defaults. +/* +/* Arguments: +/* .IP context +/* Typically, a configuration parameter name. +/* .IP protocols +/* Null-terminated string with protocol names separated by +/* whitespace and/or commas: +/* .RS +/* .IP INET_PROTO_NAME_ALL +/* Enable all available IP protocols. +/* .IP INET_PROTO_NAME_IPV4 +/* Enable IP version 4 support. +/* .IP INET_PROTO_NAME_IPV6 +/* Enable IP version 6 support. +/* .RS +/* .PP +/* Results: +/* .IP ai_family +/* Only one of PF_UNSPEC, PF_INET, or PF_INET6. This can be +/* used as input for the getaddrinfo() and getnameinfo() +/* routines. +/* .IP ai_family_list +/* One or more of PF_INET or PF_INET6. This can be used as +/* input for the inet_addr_local() routine. +/* .IP dns_atype_list +/* One or more of T_AAAA or T_A. This can be used as input for +/* the dns_lookup_v() and dns_lookup_l() routines. +/* .IP sa_family_list +/* One or more of AF_INET6 or AF_INET. This can be used as an +/* output filter for the results from the getaddrinfo() and +/* getnameinfo() routines. +/* SEE ALSO +/* msg(3) diagnostics interface +/* DIAGNOSTICS +/* This module will warn and turn off support for any protocol +/* that is requested but unavailable. +/* +/* Fatal errors: memory allocation problem. +/* LICENSE +/* .ad +/* .fi +/* The Secure Mailer license must be distributed with this software. +/* AUTHOR(S) +/* Wietse Venema +/* IBM T.J. Watson Research +/* P.O. Box 704 +/* Yorktown Heights, NY 10598, USA +/* +/* Wietse Venema +/* Google, Inc. +/* 111 8th Avenue +/* New York, NY 10011, USA +/*--*/ + +/* System library. */ + +#include <sys_defs.h> +#include <netinet/in.h> +#include <arpa/nameser.h> +#ifdef RESOLVE_H_NEEDS_STDIO_H +#include <stdio.h> +#endif +#include <resolv.h> +#include <stdarg.h> +#include <unistd.h> + +/* Utility library. */ + +#include <mymalloc.h> +#include <msg.h> +#include <myaddrinfo.h> +#include <name_mask.h> +#include <inet_proto.h> + + /* + * Application-specific. + */ + + /* + * Run-time initialization, so we can work around LINUX where IPv6 falls + * flat on its face because it is not turned on in the kernel. + */ +INET_PROTO_INFO *inet_proto_table = 0; + + /* + * Infrastructure: lookup table with the protocol names that we support. + */ +#define INET_PROTO_MASK_IPV4 (1<<0) +#define INET_PROTO_MASK_IPV6 (1<<1) + +static const NAME_MASK proto_table[] = { +#ifdef HAS_IPV6 + INET_PROTO_NAME_ALL, INET_PROTO_MASK_IPV4 | INET_PROTO_MASK_IPV6, + INET_PROTO_NAME_IPV6, INET_PROTO_MASK_IPV6, +#else + INET_PROTO_NAME_ALL, INET_PROTO_MASK_IPV4, +#endif + INET_PROTO_NAME_IPV4, INET_PROTO_MASK_IPV4, + 0, +}; + +/* make_uchar_vector - create and initialize uchar vector */ + +static unsigned char *make_uchar_vector(int len,...) +{ + const char *myname = "make_uchar_vector"; + va_list ap; + int count; + unsigned char *vp; + + va_start(ap, len); + if (len <= 0) + msg_panic("%s: bad vector length: %d", myname, len); + vp = (unsigned char *) mymalloc(sizeof(*vp) * len); + for (count = 0; count < len; count++) + vp[count] = va_arg(ap, unsigned); + va_end(ap); + return (vp); +} + +/* make_unsigned_vector - create and initialize integer vector */ + +static unsigned *make_unsigned_vector(int len,...) +{ + const char *myname = "make_unsigned_vector"; + va_list ap; + int count; + unsigned *vp; + + va_start(ap, len); + if (len <= 0) + msg_panic("%s: bad vector length: %d", myname, len); + vp = (unsigned *) mymalloc(sizeof(*vp) * len); + for (count = 0; count < len; count++) + vp[count] = va_arg(ap, unsigned); + va_end(ap); + return (vp); +} + +/* inet_proto_free - destroy data */ + +static void inet_proto_free(INET_PROTO_INFO *pf) +{ + myfree((void *) pf->ai_family_list); + myfree((void *) pf->dns_atype_list); + myfree((void *) pf->sa_family_list); + myfree((void *) pf); +} + +/* inet_proto_init - convert protocol names to library inputs */ + +const INET_PROTO_INFO *inet_proto_init(const char *context, const char *protocols) +{ + const char *myname = "inet_proto"; + INET_PROTO_INFO *pf; + int inet_proto_mask; + int sock; + + /* + * Avoid run-time errors when all network protocols are disabled. We + * can't look up interface information, and we can't convert explicit + * names or addresses. + */ + inet_proto_mask = name_mask(context, proto_table, protocols); +#ifdef HAS_IPV6 + if (inet_proto_mask & INET_PROTO_MASK_IPV6) { + if ((sock = socket(PF_INET6, SOCK_STREAM, 0)) >= 0) { + close(sock); + } else if (errno == EAFNOSUPPORT || errno == EPROTONOSUPPORT) { + msg_warn("%s: disabling IPv6 name/address support: %m", context); + inet_proto_mask &= ~INET_PROTO_MASK_IPV6; + } else { + msg_fatal("socket: %m"); + } + } +#endif + if (inet_proto_mask & INET_PROTO_MASK_IPV4) { + if ((sock = socket(PF_INET, SOCK_STREAM, 0)) >= 0) { + close(sock); + } else if (errno == EAFNOSUPPORT || errno == EPROTONOSUPPORT) { + msg_warn("%s: disabling IPv4 name/address support: %m", context); + inet_proto_mask &= ~INET_PROTO_MASK_IPV4; + } else { + msg_fatal("socket: %m"); + } + } + + /* + * Store address family etc. info as null-terminated vectors. If that + * breaks because we must be able to store nulls, we'll deal with the + * additional complexity. + * + * XXX Use compile-time initialized data templates instead of building the + * reply on the fly. + */ + switch (inet_proto_mask) { +#ifdef HAS_IPV6 + case INET_PROTO_MASK_IPV6: + pf = (INET_PROTO_INFO *) mymalloc(sizeof(*pf)); + pf->ai_family = PF_INET6; + pf->ai_family_list = make_unsigned_vector(2, PF_INET6, 0); + pf->dns_atype_list = make_unsigned_vector(2, T_AAAA, 0); + pf->sa_family_list = make_uchar_vector(2, AF_INET6, 0); + break; + case (INET_PROTO_MASK_IPV6 | INET_PROTO_MASK_IPV4): + pf = (INET_PROTO_INFO *) mymalloc(sizeof(*pf)); + pf->ai_family = PF_UNSPEC; + pf->ai_family_list = make_unsigned_vector(3, PF_INET, PF_INET6, 0); + pf->dns_atype_list = make_unsigned_vector(3, T_A, T_AAAA, 0); + pf->sa_family_list = make_uchar_vector(3, AF_INET, AF_INET6, 0); + break; +#endif + case INET_PROTO_MASK_IPV4: + pf = (INET_PROTO_INFO *) mymalloc(sizeof(*pf)); + pf->ai_family = PF_INET; + pf->ai_family_list = make_unsigned_vector(2, PF_INET, 0); + pf->dns_atype_list = make_unsigned_vector(2, T_A, 0); + pf->sa_family_list = make_uchar_vector(2, AF_INET, 0); + break; + case 0: + pf = (INET_PROTO_INFO *) mymalloc(sizeof(*pf)); + pf->ai_family = PF_UNSPEC; + pf->ai_family_list = make_unsigned_vector(1, 0); + pf->dns_atype_list = make_unsigned_vector(1, 0); + pf->sa_family_list = make_uchar_vector(1, 0); + break; + default: + msg_panic("%s: bad inet_proto_mask 0x%x", myname, inet_proto_mask); + } + if (inet_proto_table) + inet_proto_free(inet_proto_table); + return (inet_proto_table = pf); +} + +#ifdef TEST + + /* + * Small driver for unit tests. + */ + +static char *print_unsigned_vector(VSTRING *buf, unsigned *vector) +{ + unsigned *p; + + VSTRING_RESET(buf); + for (p = vector; *p; p++) { + vstring_sprintf_append(buf, "%u", *p); + if (p[1]) + VSTRING_ADDCH(buf, ' '); + } + VSTRING_TERMINATE(buf); + return (vstring_str(buf)); +} + +static char *print_uchar_vector(VSTRING *buf, unsigned char *vector) +{ + unsigned char *p; + + VSTRING_RESET(buf); + for (p = vector; *p; p++) { + vstring_sprintf_append(buf, "%u", *p); + if (p[1]) + VSTRING_ADDCH(buf, ' '); + } + VSTRING_TERMINATE(buf); + return (vstring_str(buf)); +} + +int main(int argc, char **argv) +{ + const char *myname = argv[0]; + INET_PROTO_INFO *pf; + VSTRING *buf; + + if (argc < 2) + msg_fatal("usage: %s protocol(s)...", myname); + + buf = vstring_alloc(10); + while (*++argv) { + msg_info("=== %s ===", *argv); + inet_proto_init(myname, *argv); + pf = inet_proto_table; + msg_info("ai_family = %u", pf->ai_family); + msg_info("ai_family_list = %s", + print_unsigned_vector(buf, pf->ai_family_list)); + msg_info("dns_atype_list = %s", + print_unsigned_vector(buf, pf->dns_atype_list)); + msg_info("sa_family_list = %s", + print_uchar_vector(buf, pf->sa_family_list)); + } + vstring_free(buf); + return (0); +} + +#endif |