diff options
Diffstat (limited to 'sys/netinet/libalias/alias_irc.c')
-rw-r--r-- | sys/netinet/libalias/alias_irc.c | 546 |
1 files changed, 287 insertions, 259 deletions
diff --git a/sys/netinet/libalias/alias_irc.c b/sys/netinet/libalias/alias_irc.c index 3b2ff92..5785e54 100644 --- a/sys/netinet/libalias/alias_irc.c +++ b/sys/netinet/libalias/alias_irc.c @@ -65,277 +65,305 @@ __FBSDID("$FreeBSD$"); void -AliasHandleIrcOut(struct libalias *la, - struct ip *pip, /* IP packet to examine */ - struct alias_link *link, /* Which link are we on? */ - int maxsize /* Maximum size of IP packet including headers */ - ) +AliasHandleIrcOut(struct libalias *la, + struct ip *pip, /* IP packet to examine */ + struct alias_link *link, /* Which link are we on? */ + int maxsize /* Maximum size of IP packet including + * headers */ +) { - int hlen, tlen, dlen; - struct in_addr true_addr; - u_short true_port; - char *sptr; - struct tcphdr *tc; - int i; /* Iterator through the source */ + int hlen, tlen, dlen; + struct in_addr true_addr; + u_short true_port; + char *sptr; + struct tcphdr *tc; + int i; /* Iterator through the source */ /* Calculate data length of TCP packet */ - tc = (struct tcphdr *) ((char *) pip + (pip->ip_hl << 2)); - hlen = (pip->ip_hl + tc->th_off) << 2; - tlen = ntohs(pip->ip_len); - dlen = tlen - hlen; - - /* Return if data length is too short - assume an entire PRIVMSG in each packet. */ - if (dlen<sizeof(":A!a@n.n PRIVMSG A :aDCC 1 1a")-1) - return; + tc = (struct tcphdr *)((char *)pip + (pip->ip_hl << 2)); + hlen = (pip->ip_hl + tc->th_off) << 2; + tlen = ntohs(pip->ip_len); + dlen = tlen - hlen; + + /* + * Return if data length is too short - assume an entire PRIVMSG in + * each packet. + */ + if (dlen < sizeof(":A!a@n.n PRIVMSG A :aDCC 1 1a") - 1) + return; /* Place string pointer at beginning of data */ - sptr = (char *) pip; - sptr += hlen; - maxsize -= hlen; /* We're interested in maximum size of data, not packet */ - - /* Search for a CTCP command [Note 1] */ - for( i=0; i<dlen; i++ ) { - if(sptr[i]=='\001') - goto lFOUND_CTCP; - } - return; /* No CTCP commands in */ - /* Handle CTCP commands - the buffer may have to be copied */ + sptr = (char *)pip; + sptr += hlen; + maxsize -= hlen; /* We're interested in maximum size of + * data, not packet */ + + /* Search for a CTCP command [Note 1] */ + for (i = 0; i < dlen; i++) { + if (sptr[i] == '\001') + goto lFOUND_CTCP; + } + return; /* No CTCP commands in */ + /* Handle CTCP commands - the buffer may have to be copied */ lFOUND_CTCP: - { - char newpacket[65536]; /* Estimate of maximum packet size :) */ - int copyat = i; /* Same */ - int iCopy = 0; /* How much data have we written to copy-back string? */ - unsigned long org_addr; /* Original IP address */ - unsigned short org_port; /* Original source port address */ - lCTCP_START: - if( i >= dlen || iCopy >= sizeof(newpacket) ) - goto lPACKET_DONE; - newpacket[iCopy++] = sptr[i++]; /* Copy the CTCP start character */ - /* Start of a CTCP */ - if( i+4 >= dlen ) /* Too short for DCC */ - goto lBAD_CTCP; - if( sptr[i+0] != 'D' ) - goto lBAD_CTCP; - if( sptr[i+1] != 'C' ) - goto lBAD_CTCP; - if( sptr[i+2] != 'C' ) - goto lBAD_CTCP; - if( sptr[i+3] != ' ' ) - goto lBAD_CTCP; - /* We have a DCC command - handle it! */ - i+= 4; /* Skip "DCC " */ - if( iCopy+4 > sizeof(newpacket) ) - goto lPACKET_DONE; - newpacket[iCopy++] = 'D'; - newpacket[iCopy++] = 'C'; - newpacket[iCopy++] = 'C'; - newpacket[iCopy++] = ' '; - - DBprintf(("Found DCC\n")); - /* Skip any extra spaces (should not occur according to - protocol, but DCC breaks CTCP protocol anyway */ - while(sptr[i] == ' ') { - if( ++i >= dlen) { - DBprintf(("DCC packet terminated in just spaces\n")); - goto lPACKET_DONE; - } - } - - DBprintf(("Transferring command...\n")); - while(sptr[i] != ' ') { - newpacket[iCopy++] = sptr[i]; - if( ++i >= dlen || iCopy >= sizeof(newpacket) ) { - DBprintf(("DCC packet terminated during command\n")); - goto lPACKET_DONE; - } - } - /* Copy _one_ space */ - if( i+1 < dlen && iCopy < sizeof(newpacket) ) - newpacket[iCopy++] = sptr[i++]; - - DBprintf(("Done command - removing spaces\n")); - /* Skip any extra spaces (should not occur according to - protocol, but DCC breaks CTCP protocol anyway */ - while(sptr[i] == ' ') { - if( ++i >= dlen ) { - DBprintf(("DCC packet terminated in just spaces (post-command)\n")); - goto lPACKET_DONE; - } - } - - DBprintf(("Transferring filename...\n")); - while(sptr[i] != ' ') { - newpacket[iCopy++] = sptr[i]; - if( ++i >= dlen || iCopy >= sizeof(newpacket) ) { - DBprintf(("DCC packet terminated during filename\n")); - goto lPACKET_DONE; - } - } - /* Copy _one_ space */ - if( i+1 < dlen && iCopy < sizeof(newpacket) ) - newpacket[iCopy++] = sptr[i++]; - - DBprintf(("Done filename - removing spaces\n")); - /* Skip any extra spaces (should not occur according to - protocol, but DCC breaks CTCP protocol anyway */ - while(sptr[i] == ' ') { - if( ++i >= dlen ) { - DBprintf(("DCC packet terminated in just spaces (post-filename)\n")); - goto lPACKET_DONE; - } - } - - DBprintf(("Fetching IP address\n")); - /* Fetch IP address */ - org_addr = 0; - while(i<dlen && isdigit(sptr[i])) { - if( org_addr > ULONG_MAX/10UL ) { /* Terminate on overflow */ - DBprintf(("DCC Address overflow (org_addr == 0x%08lx, next char %c\n", org_addr, sptr[i])); - goto lBAD_CTCP; - } - org_addr *= 10; - org_addr += sptr[i++]-'0'; - } - DBprintf(("Skipping space\n")); - if( i+1 >= dlen || sptr[i] != ' ' ) { - DBprintf(("Overflow (%d >= %d) or bad character (%02x) terminating IP address\n", i+1, dlen, sptr[i])); - goto lBAD_CTCP; - } - /* Skip any extra spaces (should not occur according to - protocol, but DCC breaks CTCP protocol anyway, so we might - as well play it safe */ - while(sptr[i] == ' ') { - if( ++i >= dlen ) { - DBprintf(("Packet failure - space overflow.\n")); - goto lPACKET_DONE; - } - } - DBprintf(("Fetching port number\n")); - /* Fetch source port */ - org_port = 0; - while(i<dlen && isdigit(sptr[i])) { - if( org_port > 6554 ) { /* Terminate on overflow (65536/10 rounded up*/ - DBprintf(("DCC: port number overflow\n")); - goto lBAD_CTCP; - } - org_port *= 10; - org_port += sptr[i++]-'0'; - } - /* Skip illegal addresses (or early termination) */ - if( i >= dlen || (sptr[i] != '\001' && sptr[i] != ' ') ) { - DBprintf(("Bad port termination\n")); - goto lBAD_CTCP; - } - DBprintf(("Got IP %lu and port %u\n", org_addr, (unsigned)org_port)); - - /* We've got the address and port - now alias it */ - { - struct alias_link *dcc_link; - struct in_addr destaddr; - - - true_port = htons(org_port); - true_addr.s_addr = htonl(org_addr); - destaddr.s_addr = 0; - - /* Sanity/Security checking */ - if (!org_addr || !org_port || - pip->ip_src.s_addr != true_addr.s_addr || - org_port < IPPORT_RESERVED) - goto lBAD_CTCP; - - /* Steal the FTP_DATA_PORT - it doesn't really matter, and this - would probably allow it through at least _some_ - firewalls. */ - dcc_link = FindUdpTcpOut(la, true_addr, destaddr, - true_port, 0, - IPPROTO_TCP, 1); - DBprintf(("Got a DCC link\n")); - if ( dcc_link ) { - struct in_addr alias_address; /* Address from aliasing */ - u_short alias_port; /* Port given by aliasing */ - int n; + { + char newpacket[65536]; /* Estimate of maximum packet size + * :) */ + int copyat = i; /* Same */ + int iCopy = 0; /* How much data have we written to + * copy-back string? */ + unsigned long org_addr; /* Original IP address */ + unsigned short org_port; /* Original source port + * address */ + +lCTCP_START: + if (i >= dlen || iCopy >= sizeof(newpacket)) + goto lPACKET_DONE; + newpacket[iCopy++] = sptr[i++]; /* Copy the CTCP start + * character */ + /* Start of a CTCP */ + if (i + 4 >= dlen) /* Too short for DCC */ + goto lBAD_CTCP; + if (sptr[i + 0] != 'D') + goto lBAD_CTCP; + if (sptr[i + 1] != 'C') + goto lBAD_CTCP; + if (sptr[i + 2] != 'C') + goto lBAD_CTCP; + if (sptr[i + 3] != ' ') + goto lBAD_CTCP; + /* We have a DCC command - handle it! */ + i += 4; /* Skip "DCC " */ + if (iCopy + 4 > sizeof(newpacket)) + goto lPACKET_DONE; + newpacket[iCopy++] = 'D'; + newpacket[iCopy++] = 'C'; + newpacket[iCopy++] = 'C'; + newpacket[iCopy++] = ' '; + + DBprintf(("Found DCC\n")); + /* + * Skip any extra spaces (should not occur according to + * protocol, but DCC breaks CTCP protocol anyway + */ + while (sptr[i] == ' ') { + if (++i >= dlen) { + DBprintf(("DCC packet terminated in just spaces\n")); + goto lPACKET_DONE; + } + } + + DBprintf(("Transferring command...\n")); + while (sptr[i] != ' ') { + newpacket[iCopy++] = sptr[i]; + if (++i >= dlen || iCopy >= sizeof(newpacket)) { + DBprintf(("DCC packet terminated during command\n")); + goto lPACKET_DONE; + } + } + /* Copy _one_ space */ + if (i + 1 < dlen && iCopy < sizeof(newpacket)) + newpacket[iCopy++] = sptr[i++]; + + DBprintf(("Done command - removing spaces\n")); + /* + * Skip any extra spaces (should not occur according to + * protocol, but DCC breaks CTCP protocol anyway + */ + while (sptr[i] == ' ') { + if (++i >= dlen) { + DBprintf(("DCC packet terminated in just spaces (post-command)\n")); + goto lPACKET_DONE; + } + } + + DBprintf(("Transferring filename...\n")); + while (sptr[i] != ' ') { + newpacket[iCopy++] = sptr[i]; + if (++i >= dlen || iCopy >= sizeof(newpacket)) { + DBprintf(("DCC packet terminated during filename\n")); + goto lPACKET_DONE; + } + } + /* Copy _one_ space */ + if (i + 1 < dlen && iCopy < sizeof(newpacket)) + newpacket[iCopy++] = sptr[i++]; + + DBprintf(("Done filename - removing spaces\n")); + /* + * Skip any extra spaces (should not occur according to + * protocol, but DCC breaks CTCP protocol anyway + */ + while (sptr[i] == ' ') { + if (++i >= dlen) { + DBprintf(("DCC packet terminated in just spaces (post-filename)\n")); + goto lPACKET_DONE; + } + } + + DBprintf(("Fetching IP address\n")); + /* Fetch IP address */ + org_addr = 0; + while (i < dlen && isdigit(sptr[i])) { + if (org_addr > ULONG_MAX / 10UL) { /* Terminate on overflow */ + DBprintf(("DCC Address overflow (org_addr == 0x%08lx, next char %c\n", org_addr, sptr[i])); + goto lBAD_CTCP; + } + org_addr *= 10; + org_addr += sptr[i++] - '0'; + } + DBprintf(("Skipping space\n")); + if (i + 1 >= dlen || sptr[i] != ' ') { + DBprintf(("Overflow (%d >= %d) or bad character (%02x) terminating IP address\n", i + 1, dlen, sptr[i])); + goto lBAD_CTCP; + } + /* + * Skip any extra spaces (should not occur according to + * protocol, but DCC breaks CTCP protocol anyway, so we + * might as well play it safe + */ + while (sptr[i] == ' ') { + if (++i >= dlen) { + DBprintf(("Packet failure - space overflow.\n")); + goto lPACKET_DONE; + } + } + DBprintf(("Fetching port number\n")); + /* Fetch source port */ + org_port = 0; + while (i < dlen && isdigit(sptr[i])) { + if (org_port > 6554) { /* Terminate on overflow + * (65536/10 rounded up */ + DBprintf(("DCC: port number overflow\n")); + goto lBAD_CTCP; + } + org_port *= 10; + org_port += sptr[i++] - '0'; + } + /* Skip illegal addresses (or early termination) */ + if (i >= dlen || (sptr[i] != '\001' && sptr[i] != ' ')) { + DBprintf(("Bad port termination\n")); + goto lBAD_CTCP; + } + DBprintf(("Got IP %lu and port %u\n", org_addr, (unsigned)org_port)); + + /* We've got the address and port - now alias it */ + { + struct alias_link *dcc_link; + struct in_addr destaddr; + + + true_port = htons(org_port); + true_addr.s_addr = htonl(org_addr); + destaddr.s_addr = 0; + + /* Sanity/Security checking */ + if (!org_addr || !org_port || + pip->ip_src.s_addr != true_addr.s_addr || + org_port < IPPORT_RESERVED) + goto lBAD_CTCP; + + /* + * Steal the FTP_DATA_PORT - it doesn't really + * matter, and this would probably allow it through + * at least _some_ firewalls. + */ + dcc_link = FindUdpTcpOut(la, true_addr, destaddr, + true_port, 0, + IPPROTO_TCP, 1); + DBprintf(("Got a DCC link\n")); + if (dcc_link) { + struct in_addr alias_address; /* Address from aliasing */ + u_short alias_port; /* Port given by + * aliasing */ + int n; #ifndef NO_FW_PUNCH - /* Generate firewall hole as appropriate */ - PunchFWHole(dcc_link); + /* Generate firewall hole as appropriate */ + PunchFWHole(dcc_link); #endif - alias_address = GetAliasAddress(link); - n = snprintf(&newpacket[iCopy], - sizeof(newpacket)-iCopy, - "%lu ", (u_long)htonl(alias_address.s_addr)); - if( n < 0 ) { - DBprintf(("DCC packet construct failure.\n")); - goto lBAD_CTCP; - } - if( (iCopy += n) >= sizeof(newpacket) ) { /* Truncated/fit exactly - bad news */ - DBprintf(("DCC constructed packet overflow.\n")); - goto lBAD_CTCP; - } - alias_port = GetAliasPort(dcc_link); - n = snprintf(&newpacket[iCopy], - sizeof(newpacket)-iCopy, - "%u", htons(alias_port) ); - if( n < 0 ) { - DBprintf(("DCC packet construct failure.\n")); - goto lBAD_CTCP; - } - iCopy += n; - /* Done - truncated cases will be taken care of by lBAD_CTCP */ - DBprintf(("Aliased IP %lu and port %u\n", alias_address.s_addr, (unsigned)alias_port)); - } - } - /* An uninteresting CTCP - state entered right after '\001' has - been pushed. Also used to copy the rest of a DCC, after IP - address and port has been handled */ - lBAD_CTCP: - for(; i<dlen && iCopy<sizeof(newpacket); i++,iCopy++) { - newpacket[iCopy] = sptr[i]; /* Copy CTCP unchanged */ - if(sptr[i] == '\001') { - goto lNORMAL_TEXT; - } - } - goto lPACKET_DONE; - /* Normal text */ - lNORMAL_TEXT: - for(; i<dlen && iCopy<sizeof(newpacket); i++,iCopy++) { - newpacket[iCopy] = sptr[i]; /* Copy CTCP unchanged */ - if(sptr[i] == '\001') { - goto lCTCP_START; - } - } - /* Handle the end of a packet */ - lPACKET_DONE: - iCopy = iCopy > maxsize-copyat ? maxsize-copyat : iCopy; - memcpy(sptr+copyat, newpacket, iCopy); + alias_address = GetAliasAddress(link); + n = snprintf(&newpacket[iCopy], + sizeof(newpacket) - iCopy, + "%lu ", (u_long) htonl(alias_address.s_addr)); + if (n < 0) { + DBprintf(("DCC packet construct failure.\n")); + goto lBAD_CTCP; + } + if ((iCopy += n) >= sizeof(newpacket)) { /* Truncated/fit exactly + * - bad news */ + DBprintf(("DCC constructed packet overflow.\n")); + goto lBAD_CTCP; + } + alias_port = GetAliasPort(dcc_link); + n = snprintf(&newpacket[iCopy], + sizeof(newpacket) - iCopy, + "%u", htons(alias_port)); + if (n < 0) { + DBprintf(("DCC packet construct failure.\n")); + goto lBAD_CTCP; + } + iCopy += n; + /* + * Done - truncated cases will be taken + * care of by lBAD_CTCP + */ + DBprintf(("Aliased IP %lu and port %u\n", alias_address.s_addr, (unsigned)alias_port)); + } + } + /* + * An uninteresting CTCP - state entered right after '\001' + * has been pushed. Also used to copy the rest of a DCC, + * after IP address and port has been handled + */ +lBAD_CTCP: + for (; i < dlen && iCopy < sizeof(newpacket); i++, iCopy++) { + newpacket[iCopy] = sptr[i]; /* Copy CTCP unchanged */ + if (sptr[i] == '\001') { + goto lNORMAL_TEXT; + } + } + goto lPACKET_DONE; + /* Normal text */ +lNORMAL_TEXT: + for (; i < dlen && iCopy < sizeof(newpacket); i++, iCopy++) { + newpacket[iCopy] = sptr[i]; /* Copy CTCP unchanged */ + if (sptr[i] == '\001') { + goto lCTCP_START; + } + } + /* Handle the end of a packet */ +lPACKET_DONE: + iCopy = iCopy > maxsize - copyat ? maxsize - copyat : iCopy; + memcpy(sptr + copyat, newpacket, iCopy); /* Save information regarding modified seq and ack numbers */ - { - int delta; - - SetAckModified(link); - delta = GetDeltaSeqOut(pip, link); - AddSeq(pip, link, delta+copyat+iCopy-dlen); - } - - /* Revise IP header */ - { - u_short new_len; - - new_len = htons(hlen + iCopy + copyat); - DifferentialChecksum(&pip->ip_sum, - &new_len, - &pip->ip_len, - 1); - pip->ip_len = new_len; - } - - /* Compute TCP checksum for revised packet */ - tc->th_sum = 0; - tc->th_sum = TcpChecksum(pip); - return; - } + { + int delta; + + SetAckModified(link); + delta = GetDeltaSeqOut(pip, link); + AddSeq(pip, link, delta + copyat + iCopy - dlen); + } + + /* Revise IP header */ + { + u_short new_len; + + new_len = htons(hlen + iCopy + copyat); + DifferentialChecksum(&pip->ip_sum, + &new_len, + &pip->ip_len, + 1); + pip->ip_len = new_len; + } + + /* Compute TCP checksum for revised packet */ + tc->th_sum = 0; + tc->th_sum = TcpChecksum(pip); + return; + } } /* Notes: |