diff options
Diffstat (limited to 'lib/libalias/alias.c')
| -rw-r--r-- | lib/libalias/alias.c | 135 |
1 files changed, 134 insertions, 1 deletions
diff --git a/lib/libalias/alias.c b/lib/libalias/alias.c index e4770fe..d70efb8 100644 --- a/lib/libalias/alias.c +++ b/lib/libalias/alias.c @@ -76,9 +76,13 @@ Version 2.3 Dec 1998 (dillon) - Major bounds checking additions, see FreeBSD/CVS - Version 3.1 May, 2000 (eds) + Version 3.1 May, 2000 (salander) - Added hooks to handle PPTP. + Version 3.2 July, 2000 (salander and satoh) + - Added PacketUnaliasOut routine. + - Added hooks to handle RTSP/RTP. + See HISTORY file for additional revisions. $FreeBSD$ @@ -102,6 +106,8 @@ #define IRC_CONTROL_PORT_NUMBER_1 6667 #define IRC_CONTROL_PORT_NUMBER_2 6668 #define CUSEEME_PORT_NUMBER 7648 +#define RTSP_CONTROL_PORT_NUMBER_1 554 +#define RTSP_CONTROL_PORT_NUMBER_2 7070 #define PPTP_CONTROL_PORT_NUMBER 1723 @@ -1112,6 +1118,11 @@ TcpAliasOut(struct ip *pip, int maxpacketsize) else if (ntohs(tc->th_dport) == IRC_CONTROL_PORT_NUMBER_1 || ntohs(tc->th_dport) == IRC_CONTROL_PORT_NUMBER_2) AliasHandleIrcOut(pip, link, maxpacketsize); + else if (ntohs(tc->th_dport) == RTSP_CONTROL_PORT_NUMBER_1 + || ntohs(tc->th_sport) == RTSP_CONTROL_PORT_NUMBER_1 + || ntohs(tc->th_dport) == RTSP_CONTROL_PORT_NUMBER_2 + || ntohs(tc->th_sport) == RTSP_CONTROL_PORT_NUMBER_2) + AliasHandleRtspOut(pip, link, maxpacketsize); else if (ntohs(tc->th_dport) == PPTP_CONTROL_PORT_NUMBER || ntohs(tc->th_sport) == PPTP_CONTROL_PORT_NUMBER) AliasHandlePptpOut(pip, link); @@ -1236,6 +1247,7 @@ FragmentOut(struct ip *pip) PacketAliasFragmentIn() PacketAliasIn() PacketAliasOut() + PacketUnaliasOut() (prototypes in alias.h) */ @@ -1465,3 +1477,124 @@ PacketAliasOut(char *ptr, /* valid IP packet */ SetDefaultAliasAddress(addr_save); return(iresult); } + +int +PacketUnaliasOut(char *ptr, /* valid IP packet */ + int maxpacketsize /* for error checking */ + ) +{ + struct ip *pip; + struct icmp *ic; + struct udphdr *ud; + struct tcphdr *tc; + struct alias_link *link; + int iresult = PKT_ALIAS_IGNORED; + + pip = (struct ip *) ptr; + + /* Defense against mangled packets */ + if (ntohs(pip->ip_len) > maxpacketsize + || (pip->ip_hl<<2) > maxpacketsize) + return(iresult); + + ud = (struct udphdr *) ((char *) pip + (pip->ip_hl << 2)); + tc = (struct tcphdr *) ud; + ic = (struct icmp *) ud; + + /* Find a link */ + if (pip->ip_p == IPPROTO_UDP) + link = QueryUdpTcpIn(pip->ip_dst, pip->ip_src, + ud->uh_dport, ud->uh_sport, + IPPROTO_UDP); + else if (pip->ip_p == IPPROTO_TCP) + link = QueryUdpTcpIn(pip->ip_dst, pip->ip_src, + tc->th_dport, tc->th_sport, + IPPROTO_TCP); + else if (pip->ip_p == IPPROTO_ICMP) + link = FindIcmpIn(pip->ip_dst, pip->ip_src, ic->icmp_id); + else + link = NULL; + + /* Change it from an aliased packet to an unaliased packet */ + if (link != NULL) + { + if (pip->ip_p == IPPROTO_UDP || pip->ip_p == IPPROTO_TCP) + { + u_short *sptr; + int accumulate; + struct in_addr original_address; + u_short original_port; + + original_address = GetOriginalAddress(link); + original_port = GetOriginalPort(link); + + /* Adjust TCP/UDP checksum */ + sptr = (u_short *) &(pip->ip_src); + accumulate = *sptr++; + accumulate += *sptr; + sptr = (u_short *) &original_address; + accumulate -= *sptr++; + accumulate -= *sptr; + + if (pip->ip_p == IPPROTO_UDP) { + accumulate += ud->uh_sport; + accumulate -= original_port; + ADJUST_CHECKSUM(accumulate, ud->uh_sum) + } else { + accumulate += tc->th_sport; + accumulate -= original_port; + ADJUST_CHECKSUM(accumulate, tc->th_sum) + } + + /* Adjust IP checksum */ + DifferentialChecksum(&pip->ip_sum, + (u_short *) &original_address, + (u_short *) &pip->ip_src, + 2); + + /* Un-alias source address and port number */ + pip->ip_src = original_address; + if (pip->ip_p == IPPROTO_UDP) + ud->uh_sport = original_port; + else + tc->th_sport = original_port; + + iresult = PKT_ALIAS_OK; + + } else if (pip->ip_p == IPPROTO_ICMP) { + + u_short *sptr; + int accumulate; + struct in_addr original_address; + u_short original_id; + + original_address = GetOriginalAddress(link); + original_id = GetOriginalPort(link); + + /* Adjust ICMP checksum */ + sptr = (u_short *) &(pip->ip_src); + accumulate = *sptr++; + accumulate += *sptr; + sptr = (u_short *) &original_address; + accumulate -= *sptr++; + accumulate -= *sptr; + accumulate += ic->icmp_id; + accumulate -= original_id; + ADJUST_CHECKSUM(accumulate, ic->icmp_cksum) + + /* Adjust IP checksum */ + DifferentialChecksum(&pip->ip_sum, + (u_short *) &original_address, + (u_short *) &pip->ip_src, + 2); + + /* Un-alias source address and port number */ + pip->ip_src = original_address; + ic->icmp_id = original_id; + + iresult = PKT_ALIAS_OK; + } + } + return(iresult); + +} |
