/* * Copyright (C) 1997 by Darren Reed. * * Redistribution and use in source and binary forms are permitted * provided that this notice is preserved and due credit is given * to the original author and the contributors. */ #if !defined(lint) static const char rcsid[] = "@(#)$Id: ip_proxy.c,v 1.1.1.3 1998/03/21 10:11:30 peter Exp $"; #endif #if defined(__FreeBSD__) && defined(KERNEL) && !defined(_KERNEL) # define _KERNEL #endif #if !defined(_KERNEL) && !defined(KERNEL) # include # include # include #endif #include #include #include #include #include #if !defined(__FreeBSD__) # include #endif #include #include #ifndef linux # include #endif #include #if defined(_KERNEL) # if !defined(linux) # include # else # include # endif #endif #if !defined(__SVR4) && !defined(__svr4__) # ifndef linux # include # endif #else # include # include # include # include #endif #if __FreeBSD__ > 2 # include # include #endif #include #ifdef sun # include #endif #include #include #include #include #ifndef linux # include #endif #include #include #include #include "netinet/ip_compat.h" #include #include "netinet/ip_fil.h" #include "netinet/ip_proxy.h" #include "netinet/ip_nat.h" #include "netinet/ip_state.h" #ifndef MIN #define MIN(a,b) (((a)<(b))?(a):(b)) #endif static ap_session_t *ap_find __P((ip_t *, tcphdr_t *)); static ap_session_t *ap_new_session __P((aproxy_t *, ip_t *, tcphdr_t *, fr_info_t *, nat_t *)); #define AP_SESS_SIZE 53 #if defined(_KERNEL) && !defined(linux) #include "netinet/ip_ftp_pxy.c" #endif ap_session_t *ap_sess_tab[AP_SESS_SIZE]; aproxy_t ap_proxies[] = { #ifdef IPF_FTP_PROXY { "ftp", (char)IPPROTO_TCP, 0, 0, ippr_ftp_init, ippr_ftp_in, ippr_ftp_out }, #endif { "", '\0', 0, 0, NULL, NULL } }; int ap_ok(ip, tcp, nat) ip_t *ip; tcphdr_t *tcp; ipnat_t *nat; { aproxy_t *apr = nat->in_apr; u_short dport = nat->in_dport; if (!apr || (apr && (apr->apr_flags & APR_DELETE)) || (ip->ip_p != apr->apr_p)) return 0; if ((tcp && (tcp->th_dport != dport)) || (!tcp && dport)) return 0; return 1; } static ap_session_t *ap_find(ip, tcp) ip_t *ip; tcphdr_t *tcp; { struct in_addr src, dst; register u_long hv; register u_short sp, dp; register ap_session_t *aps; register u_char p = ip->ip_p; src = ip->ip_src, dst = ip->ip_dst; sp = dp = 0; /* XXX gcc -Wunitialized */ hv = ip->ip_src.s_addr ^ ip->ip_dst.s_addr; hv *= 651733; if (tcp) { sp = tcp->th_sport; dp = tcp->th_dport; hv ^= (sp + dp); hv *= 5; } hv %= AP_SESS_SIZE; for (aps = ap_sess_tab[hv]; aps; aps = aps->aps_next) if ((aps->aps_p == p) && IPPAIR(aps->aps_src, aps->aps_dst, src, dst)) { if (tcp) { if (PAIRS(aps->aps_sport, aps->aps_dport, sp, dp)) break; } else break; } return aps; } /* * Allocate a new application proxy structure and fill it in with the * relevant details. call the init function once complete, prior to * returning. */ static ap_session_t *ap_new_session(apr, ip, tcp, fin, nat) aproxy_t *apr; ip_t *ip; tcphdr_t *tcp; fr_info_t *fin; nat_t *nat; { register ap_session_t *aps; u_short dport; u_long hv; if (!apr || (apr && (apr->apr_flags & APR_DELETE)) || (ip->ip_p != apr->apr_p)) return NULL; dport = nat->nat_ptr->in_dport; if ((tcp && (tcp->th_dport != dport)) || (!tcp && dport)) return NULL; hv = ip->ip_src.s_addr ^ ip->ip_dst.s_addr; hv *= 651733; if (tcp) { hv ^= (tcp->th_sport + tcp->th_dport); hv *= 5; } hv %= AP_SESS_SIZE; KMALLOC(aps, ap_session_t *, sizeof(*aps)); if (!aps) return NULL; bzero((char *)aps, sizeof(*aps)); aps->aps_apr = apr; aps->aps_src = ip->ip_src; aps->aps_dst = ip->ip_dst; aps->aps_p = ip->ip_p; aps->aps_tout = 1200; /* XXX */ if (tcp) { aps->aps_sport = tcp->th_sport; aps->aps_dport = tcp->th_dport; } aps->aps_data = NULL; aps->aps_psiz = 0; aps->aps_next = ap_sess_tab[hv]; ap_sess_tab[hv] = aps; (void) (*apr->apr_init)(fin, ip, tcp, aps, nat); return aps; } /* * check to see if a packet should be passed through an active proxy routine * if one has been setup for it. */ int ap_check(ip, tcp, fin, nat) ip_t *ip; tcphdr_t *tcp; fr_info_t *fin; nat_t *nat; { ap_session_t *aps; aproxy_t *apr; int err; if (!(fin->fin_fi.fi_fl & FI_TCPUDP)) tcp = NULL; if ((aps = ap_find(ip, tcp)) || (aps = ap_new_session(nat->nat_ptr->in_apr, ip, tcp, fin, nat))) { if (ip->ip_p == IPPROTO_TCP) { /* * verify that the checksum is correct. If not, then * don't do anything with this packet. */ if (tcp->th_sum != fr_tcpsum(*(mb_t **)fin->fin_mp, ip, tcp, ip->ip_len)) { frstats[fin->fin_out].fr_tcpbad++; return -1; } fr_tcp_age(&aps->aps_tout, aps->aps_state, ip, fin, tcp->th_sport == aps->aps_sport); } apr = aps->aps_apr; err = 0; if (fin->fin_out) { if (apr->apr_outpkt) err = (*apr->apr_outpkt)(fin, ip, tcp, aps, nat); } else { if (apr->apr_inpkt) err = (*apr->apr_inpkt)(fin, ip, tcp, aps, nat); } if (err == 2) { tcp->th_sum = fr_tcpsum(*(mb_t **)fin->fin_mp, ip, tcp, ip->ip_len); err = 0; } return err; } return -1; } aproxy_t *ap_match(pr, name) u_char pr; char *name; { aproxy_t *ap; for (ap = ap_proxies; ap->apr_p; ap++) if ((ap->apr_p == pr) && !strncmp(name, ap->apr_label, sizeof(ap->apr_label))) { ap->apr_ref++; return ap; } return NULL; } void ap_free(ap) aproxy_t *ap; { ap->apr_ref--; } void aps_free(aps) ap_session_t *aps; { if (aps->aps_data && aps->aps_psiz) KFREES(aps->aps_data, aps->aps_psiz); KFREE(aps); } void ap_unload() { ap_session_t *aps; int i; for (i = 0; i < AP_SESS_SIZE; i++) while ((aps = ap_sess_tab[i])) { ap_sess_tab[i] = aps->aps_next; aps_free(aps); } } void ap_expire() { ap_session_t *aps, **apsp; int i; for (i = 0; i < AP_SESS_SIZE; i++) for (apsp = &ap_sess_tab[i]; (aps = *apsp); ) { aps->aps_tout--; if (!aps->aps_tout) { ap_sess_tab[i] = aps->aps_next; aps_free(aps); *apsp = aps->aps_next; } else apsp = &aps->aps_next; } }