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alias_db.c (62159) alias_db.c (63899)
1/* -*- mode: c; tab-width: 8; c-basic-indent: 4; -*-
2 Alias_db.c encapsulates all data structures used for storing
3 packet aliasing data. Other parts of the aliasing software
4 access data through functions provided in this file.
5
6 Data storage is based on the notion of a "link", which is
7 established for ICMP echo/reply packets, UDP datagrams and
8 TCP stream connections. A link stores the original source

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98 multiple external addresses rather than just a single
99 host address.
100
101 PacketAliasRedirectPort() and PacketAliasRedirectAddr()
102 added to the API. The first function is a more generalized
103 version of PacketAliasPermanentLink(). The second function
104 implements static network address translation.
105
1/* -*- mode: c; tab-width: 8; c-basic-indent: 4; -*-
2 Alias_db.c encapsulates all data structures used for storing
3 packet aliasing data. Other parts of the aliasing software
4 access data through functions provided in this file.
5
6 Data storage is based on the notion of a "link", which is
7 established for ICMP echo/reply packets, UDP datagrams and
8 TCP stream connections. A link stores the original source

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98 multiple external addresses rather than just a single
99 host address.
100
101 PacketAliasRedirectPort() and PacketAliasRedirectAddr()
102 added to the API. The first function is a more generalized
103 version of PacketAliasPermanentLink(). The second function
104 implements static network address translation.
105
106 Version 3.2: July, 2000 (salander and satoh)
107 Added FindNewPortGroup to get contiguous range of port values.
108
109 Added QueryUdpTcpIn and QueryUdpTcpOut to look for an aliasing
110 link but not actually add one.
111
112 Added FindRtspOut, which is closely derived from FindUdpTcpOut,
113 except that the alias port (from FindNewPortGroup) is provided
114 as input.
115
106 See HISTORY file for additional revisions.
107
116 See HISTORY file for additional revisions.
117
108 $FreeBSD: head/sys/netinet/libalias/alias_db.c 62159 2000-06-27 14:56:07Z ru $
118 $FreeBSD: head/sys/netinet/libalias/alias_db.c 63899 2000-07-26 23:15:46Z archie $
109*/
110
111
112/* System include files */
113#include <errno.h>
114#include <stdlib.h>
115#include <stdio.h>
116#include <unistd.h>

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495 IncrementalCleanup() - look for stale links in a single chain
496 DeleteLink() - remove link
497 AddLink() - add link
498 ReLink() - change link
499
500Link search:
501 FindLinkOut() - find link for outgoing packets
502 FindLinkIn() - find link for incoming packets
119*/
120
121
122/* System include files */
123#include <errno.h>
124#include <stdlib.h>
125#include <stdio.h>
126#include <unistd.h>

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505 IncrementalCleanup() - look for stale links in a single chain
506 DeleteLink() - remove link
507 AddLink() - add link
508 ReLink() - change link
509
510Link search:
511 FindLinkOut() - find link for outgoing packets
512 FindLinkIn() - find link for incoming packets
513
514Port search:
515 FindNewPortGroup() - find an available group of ports
503*/
504
505/* Local prototypes */
506static int GetNewPort(struct alias_link *, int);
507
508static u_short GetSocket(u_short, int *, int);
509
510static void CleanupAliasData(void);

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526FindLinkOut(struct in_addr, struct in_addr, u_short, u_short, int, int);
527
528static struct alias_link *
529FindLinkIn(struct in_addr, struct in_addr, u_short, u_short, int, int);
530
531
532#define ALIAS_PORT_BASE 0x08000
533#define ALIAS_PORT_MASK 0x07fff
516*/
517
518/* Local prototypes */
519static int GetNewPort(struct alias_link *, int);
520
521static u_short GetSocket(u_short, int *, int);
522
523static void CleanupAliasData(void);

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539FindLinkOut(struct in_addr, struct in_addr, u_short, u_short, int, int);
540
541static struct alias_link *
542FindLinkIn(struct in_addr, struct in_addr, u_short, u_short, int, int);
543
544
545#define ALIAS_PORT_BASE 0x08000
546#define ALIAS_PORT_MASK 0x07fff
547#define ALIAS_PORT_MASK_EVEN 0x07ffe
534#define GET_NEW_PORT_MAX_ATTEMPTS 20
535
536#define GET_ALIAS_PORT -1
537#define GET_ALIAS_ID GET_ALIAS_PORT
538
548#define GET_NEW_PORT_MAX_ATTEMPTS 20
549
550#define GET_ALIAS_PORT -1
551#define GET_ALIAS_ID GET_ALIAS_PORT
552
553#define FIND_EVEN_ALIAS_BASE 1
554
539/* GetNewPort() allocates port numbers. Note that if a port number
540 is already in use, that does not mean that it cannot be used by
541 another link concurrently. This is because GetNewPort() looks for
542 unused triplets: (dest addr, dest port, alias port). */
543
544static int
545GetNewPort(struct alias_link *link, int alias_port_param)
546{

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699 else
700 {
701 close(sock);
702 return(0);
703 }
704}
705
706
555/* GetNewPort() allocates port numbers. Note that if a port number
556 is already in use, that does not mean that it cannot be used by
557 another link concurrently. This is because GetNewPort() looks for
558 unused triplets: (dest addr, dest port, alias port). */
559
560static int
561GetNewPort(struct alias_link *link, int alias_port_param)
562{

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715 else
716 {
717 close(sock);
718 return(0);
719 }
720}
721
722
723/* FindNewPortGroup() returns a base port number for an available
724 range of contiguous port numbers. Note that if a port number
725 is already in use, that does not mean that it cannot be used by
726 another link concurrently. This is because FindNewPortGroup()
727 looks for unused triplets: (dest addr, dest port, alias port). */
728
729int
730FindNewPortGroup(struct in_addr dst_addr,
731 struct in_addr alias_addr,
732 u_short src_port,
733 u_short dst_port,
734 u_short port_count,
735 u_char proto,
736 u_char align)
737{
738 int i, j;
739 int max_trials;
740 u_short port_sys;
741 int link_type;
742
743 /*
744 * Get link_type from protocol
745 */
746
747 switch (proto)
748 {
749 case IPPROTO_UDP:
750 link_type = LINK_UDP;
751 break;
752 case IPPROTO_TCP:
753 link_type = LINK_TCP;
754 break;
755 default:
756 return (0);
757 break;
758 }
759
760 /*
761 * The aliasing port is automatically selected
762 * by one of two methods below:
763 */
764 max_trials = GET_NEW_PORT_MAX_ATTEMPTS;
765
766 if (packetAliasMode & PKT_ALIAS_SAME_PORTS) {
767 /*
768 * When the ALIAS_SAME_PORTS option is
769 * chosen, the first try will be the
770 * actual source port. If this is already
771 * in use, the remainder of the trials
772 * will be random.
773 */
774 port_sys = ntohs(src_port);
775
776 } else {
777
778 /* First trial and all subsequent are random. */
779 if (align == FIND_EVEN_ALIAS_BASE)
780 port_sys = random() & ALIAS_PORT_MASK_EVEN;
781 else
782 port_sys = random() & ALIAS_PORT_MASK;
783
784 port_sys += ALIAS_PORT_BASE;
785 }
786
787/* Port number search */
788 for (i = 0; i < max_trials; i++) {
789
790 struct alias_link *search_result;
791
792 for (j = 0; j < port_count; j++)
793 if (0 != (search_result = FindLinkIn(dst_addr, alias_addr,
794 dst_port, htons(port_sys + j),
795 link_type, 0)))
796 break;
797
798 /* Found a good range, return base */
799 if (j == port_count)
800 return (htons(port_sys));
801
802 /* Find a new base to try */
803 if (align == FIND_EVEN_ALIAS_BASE)
804 port_sys = random() & ALIAS_PORT_MASK_EVEN;
805 else
806 port_sys = random() & ALIAS_PORT_MASK;
807
808 port_sys += ALIAS_PORT_BASE;
809 }
810
811#ifdef DEBUG
812 fprintf(stderr, "PacketAlias/FindNewPortGroup(): ");
813 fprintf(stderr, "could not find free port(s)\n");
814#endif
815
816 return(0);
817}
818
707static void
708CleanupAliasData(void)
709{
710 struct alias_link *link;
711 int i, icount;
712
713 icount = 0;
714 for (i=0; i<LINK_TABLE_OUT_SIZE; i++)

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1595 call_id, NO_DEST_PORT, GET_ALIAS_PORT,
1596 LINK_PPTP);
1597 }
1598
1599 return(link);
1600}
1601
1602
819static void
820CleanupAliasData(void)
821{
822 struct alias_link *link;
823 int i, icount;
824
825 icount = 0;
826 for (i=0; i<LINK_TABLE_OUT_SIZE; i++)

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1707 call_id, NO_DEST_PORT, GET_ALIAS_PORT,
1708 LINK_PPTP);
1709 }
1710
1711 return(link);
1712}
1713
1714
1715struct alias_link *
1716QueryUdpTcpIn(struct in_addr dst_addr,
1717 struct in_addr alias_addr,
1718 u_short dst_port,
1719 u_short alias_port,
1720 u_char proto)
1721{
1722 int link_type;
1723 struct alias_link *link;
1724
1725 switch (proto)
1726 {
1727 case IPPROTO_UDP:
1728 link_type = LINK_UDP;
1729 break;
1730 case IPPROTO_TCP:
1731 link_type = LINK_TCP;
1732 break;
1733 default:
1734 return NULL;
1735 break;
1736 }
1737
1738 link = FindLinkIn(dst_addr, alias_addr,
1739 dst_port, alias_port,
1740 link_type, 0);
1741
1742 return(link);
1743}
1744
1745
1746struct alias_link *
1747QueryUdpTcpOut(struct in_addr src_addr,
1748 struct in_addr dst_addr,
1749 u_short src_port,
1750 u_short dst_port,
1751 u_char proto)
1752{
1753 int link_type;
1754 struct alias_link *link;
1755
1756 switch (proto)
1757 {
1758 case IPPROTO_UDP:
1759 link_type = LINK_UDP;
1760 break;
1761 case IPPROTO_TCP:
1762 link_type = LINK_TCP;
1763 break;
1764 default:
1765 return NULL;
1766 break;
1767 }
1768
1769 link = FindLinkOut(src_addr, dst_addr,
1770 src_port, dst_port,
1771 link_type, 0);
1772
1773 return(link);
1774}
1775
1776
1777struct alias_link *
1778FindRtspOut(struct in_addr src_addr,
1779 struct in_addr dst_addr,
1780 u_short src_port,
1781 u_short alias_port,
1782 u_char proto)
1783{
1784 int link_type;
1785 struct alias_link *link;
1786
1787 switch (proto)
1788 {
1789 case IPPROTO_UDP:
1790 link_type = LINK_UDP;
1791 break;
1792 case IPPROTO_TCP:
1793 link_type = LINK_TCP;
1794 break;
1795 default:
1796 return NULL;
1797 break;
1798 }
1799
1800 link = FindLinkOut(src_addr, dst_addr, src_port, 0, link_type, 1);
1801
1802 if (link == NULL)
1803 {
1804 struct in_addr alias_addr;
1805
1806 alias_addr = FindAliasAddress(src_addr);
1807 link = AddLink(src_addr, dst_addr, alias_addr,
1808 src_port, 0, alias_port,
1809 link_type);
1810 }
1811
1812 return(link);
1813}
1814
1815
1603struct in_addr
1604FindOriginalAddress(struct in_addr alias_addr)
1605{
1606 struct alias_link *link;
1607
1608 link = FindLinkIn(nullAddress, alias_addr,
1609 0, 0, LINK_ADDR, 0);
1610 if (link == NULL)

--- 1003 unchanged lines hidden --- 		1816struct in_addr
1817FindOriginalAddress(struct in_addr alias_addr)
1818{
1819 struct alias_link *link;
1820
1821 link = FindLinkIn(nullAddress, alias_addr,
1822 0, 0, LINK_ADDR, 0);
1823 if (link == NULL)

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