sock_addr.c

[詳解]

/*++
/* NAME
/*  sock_addr 3
/* SUMMARY
/*  sockaddr utilities
/* SYNOPSIS
/*  #include <sock_addr.h>
/*
/*  int sock_addr_cmp_addr(sa, sb)
/*  const struct sockaddr *sa;
/*  const struct sockaddr *sb;
/*
/*  int sock_addr_cmp_port(sa, sb)
/*  const struct sockaddr *sa;
/*  const struct sockaddr *sb;
/*
/*  int SOCK_ADDR_EQ_ADDR(sa, sb)
/*  const struct sockaddr *sa;
/*  const struct sockaddr *sb;
/*
/*  int SOCK_ADDR_EQ_PORT(sa, sb)
/*  const struct sockaddr *sa;
/*  const struct sockaddr *sb;
/*
/*  int sock_addr_in_loopback(sa)
/*  const struct sockaddr *sa;
/* AUXILIARY MACROS
/*  struct sockaddr *SOCK_ADDR_PTR(ptr)
/*  unsigned char SOCK_ADDR_FAMILY(ptr)
/*  unsigned char SOCK_ADDR_LEN(ptr)
/*  unsigned short SOCK_ADDR_PORT(ptr)
/*  unsigned short *SOCK_ADDR_PORTP(ptr)
/*
/*  struct sockaddr_in *SOCK_ADDR_IN_PTR(ptr)
/*  unsigned char SOCK_ADDR_IN_FAMILY(ptr)
/*  unsigned short SOCK_ADDR_IN_PORT(ptr)
/*  struct in_addr SOCK_ADDR_IN_ADDR(ptr)
/*  struct in_addr IN_ADDR(ptr)
/*
/*  struct sockaddr_in6 *SOCK_ADDR_IN6_PTR(ptr)
/*  unsigned char SOCK_ADDR_IN6_FAMILY(ptr)
/*  unsigned short SOCK_ADDR_IN6_PORT(ptr)
/*  struct in6_addr SOCK_ADDR_IN6_ADDR(ptr)
/*  struct in6_addr IN6_ADDR(ptr)
/* DESCRIPTION
/*  These utilities take protocol-independent address structures
/*  and perform protocol-dependent operations on structure members.
/*  Some of the macros described here are called unsafe,
/*  because they evaluate one or more arguments multiple times.
/*
/*  sock_addr_cmp_addr() or sock_addr_cmp_port() compare the
/*  address family and network address or port fields for
/*  equality, and return indication of the difference between
/*  their arguments:  < 0 if the first argument is "smaller",
/*  0 for equality, and > 0 if the first argument is "larger".
/*
/*  The unsafe macros SOCK_ADDR_EQ_ADDR() or SOCK_ADDR_EQ_PORT()
/*  compare compare the address family and network address or
/*  port fields for equality, and return non-zero when their
/*  arguments differ.
/*
/*  sock_addr_in_loopback() determines if the argument specifies
/*  a loopback address.
/*
/*  The SOCK_ADDR_PTR() macro casts a generic pointer to (struct
/*  sockaddr *).  The name is upper case for consistency not
/*  safety.  SOCK_ADDR_FAMILY() and SOCK_ADDR_LEN() return the
/*  address family and length of the real structure that hides
/*  inside a generic sockaddr structure. On systems where struct
/*  sockaddr has no sa_len member, SOCK_ADDR_LEN() cannot be
/*  used as lvalue. SOCK_ADDR_PORT() returns the IPv4 or IPv6
/*  port number, in network byte order; it must not be used as
/*  lvalue. SOCK_ADDR_PORTP() returns a pointer to the same.
/*
/*  The macros SOCK_ADDR_IN{,6}_{PTR,FAMILY,PORT,ADDR}() cast
/*  a generic pointer to a specific socket address structure
/*  pointer, or access a specific socket address structure
/*  member. These can be used as lvalues.
/*
/*  The unsafe INADDR() and IN6_ADDR() macros dereference a
/*  generic pointer to a specific address structure.
/* DIAGNOSTICS
/*  Panic: unsupported address family.
/* 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
/*--*/

/* System library. */

#include <sys_defs.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <string.h>

/* Utility library. */

#include <msg.h>
#include <sock_addr.h>

/* sock_addr_cmp_addr - compare addresses for equality */

int     sock_addr_cmp_addr(const struct sockaddr *sa,
                       const struct sockaddr *sb)
{
    if (sa->sa_family != sb->sa_family)
    return (sa->sa_family - sb->sa_family);

    /*
     * With IPv6 address structures, assume a non-hostile implementation that
     * stores the address as a contiguous sequence of bits. Any holes in the
     * sequence would invalidate the use of memcmp().
     */
    if (sa->sa_family == AF_INET) {
    return (SOCK_ADDR_IN_ADDR(sa).s_addr - SOCK_ADDR_IN_ADDR(sb).s_addr);
#ifdef HAS_IPV6
    } else if (sa->sa_family == AF_INET6) {
    return (memcmp((void *) &(SOCK_ADDR_IN6_ADDR(sa)),
               (void *) &(SOCK_ADDR_IN6_ADDR(sb)),
               sizeof(SOCK_ADDR_IN6_ADDR(sa))));
#endif
    } else {
    msg_panic("sock_addr_cmp_addr: unsupported address family %d",
          sa->sa_family);
    }
}

/* sock_addr_cmp_port - compare ports for equality */

int     sock_addr_cmp_port(const struct sockaddr *sa,
                       const struct sockaddr *sb)
{
    if (sa->sa_family != sb->sa_family)
    return (sa->sa_family - sb->sa_family);

    if (sa->sa_family == AF_INET) {
    return (SOCK_ADDR_IN_PORT(sa) - SOCK_ADDR_IN_PORT(sb));
#ifdef HAS_IPV6
    } else if (sa->sa_family == AF_INET6) {
    return (SOCK_ADDR_IN6_PORT(sa) - SOCK_ADDR_IN6_PORT(sb));
#endif
    } else {
    msg_panic("sock_addr_cmp_port: unsupported address family %d",
          sa->sa_family);
    }
}

/* sock_addr_in_loopback - determine if address is loopback */

int     sock_addr_in_loopback(const struct sockaddr *sa)
{
    unsigned long inaddr;

    if (sa->sa_family == AF_INET) {
    inaddr = ntohl(SOCK_ADDR_IN_ADDR(sa).s_addr);
    return (IN_CLASSA(inaddr)
        && ((inaddr & IN_CLASSA_NET) >> IN_CLASSA_NSHIFT)
        == IN_LOOPBACKNET);
#ifdef HAS_IPV6
    } else if (sa->sa_family == AF_INET6) {
    return (IN6_IS_ADDR_LOOPBACK(&SOCK_ADDR_IN6_ADDR(sa)));
#endif
    } else {
    msg_panic("sock_addr_in_loopback: unsupported address family %d",
          sa->sa_family);
    }
}