485 lines
10 KiB
C
485 lines
10 KiB
C
/* $NetBSD: ip_tftp_pxy.c,v 1.5 2012/07/30 19:27:47 pgoyette Exp $ */
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/*
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* Copyright (C) 2012 by Darren Reed.
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*
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* See the IPFILTER.LICENCE file for details on licencing.
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*
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* Id: ip_tftp_pxy.c,v 1.1.1.2 2012/07/22 13:45:38 darrenr Exp
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*/
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#define IPF_TFTP_PROXY
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typedef struct ipf_tftp_softc_s {
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int ipf_p_tftp_readonly;
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ipftuneable_t *ipf_p_tftp_tune;
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} ipf_tftp_softc_t;
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int ipf_p_tftp_backchannel(fr_info_t *, ap_session_t *, nat_t *);
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int ipf_p_tftp_client(ipf_tftp_softc_t *, fr_info_t *, ap_session_t *,
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nat_t *);
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int ipf_p_tftp_in(void *, fr_info_t *, ap_session_t *, nat_t *);
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void ipf_p_tftp_main_load(void);
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void ipf_p_tftp_main_unload(void);
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int ipf_p_tftp_new(void *, fr_info_t *, ap_session_t *, nat_t *);
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void ipf_p_tftp_del(ipf_main_softc_t *, ap_session_t *);
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int ipf_p_tftp_out(void *, fr_info_t *, ap_session_t *, nat_t *);
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int ipf_p_tftp_server(ipf_tftp_softc_t *, fr_info_t *, ap_session_t *,
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nat_t *);
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void *ipf_p_tftp_soft_create(ipf_main_softc_t *);
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void ipf_p_tftp_soft_destroy(ipf_main_softc_t *, void *);
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static frentry_t tftpfr;
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static int tftp_proxy_init = 0;
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typedef enum tftp_cmd_e {
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TFTP_CMD_READ = 1,
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TFTP_CMD_WRITE = 2,
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TFTP_CMD_DATA = 3,
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TFTP_CMD_ACK = 4,
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TFTP_CMD_ERROR = 5
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} tftp_cmd_t;
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typedef struct tftpinfo {
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tftp_cmd_t ti_lastcmd;
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int ti_nextblk;
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int ti_lastblk;
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int ti_lasterror;
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char ti_filename[80];
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ipnat_t *ti_rule;
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} tftpinfo_t;
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static ipftuneable_t ipf_tftp_tuneables[] = {
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{ { (void *)offsetof(ipf_tftp_softc_t, ipf_p_tftp_readonly) },
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"tftp_read_only", 0, 1,
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stsizeof(ipf_tftp_softc_t, ipf_p_tftp_readonly),
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0, NULL, NULL },
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{ { NULL }, NULL, 0, 0, 0, 0, NULL, NULL }
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};
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/*
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* TFTP application proxy initialization.
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*/
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void
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ipf_p_tftp_main_load(void)
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{
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bzero((char *)&tftpfr, sizeof(tftpfr));
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tftpfr.fr_ref = 1;
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tftpfr.fr_flags = FR_INQUE|FR_PASS|FR_QUICK|FR_KEEPSTATE;
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MUTEX_INIT(&tftpfr.fr_lock, "TFTP proxy rule lock");
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tftp_proxy_init = 1;
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}
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void
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ipf_p_tftp_main_unload(void)
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{
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if (tftp_proxy_init == 1) {
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MUTEX_DESTROY(&tftpfr.fr_lock);
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tftp_proxy_init = 0;
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}
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}
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void *
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ipf_p_tftp_soft_create(ipf_main_softc_t *softc)
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{
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ipf_tftp_softc_t *softt;
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KMALLOC(softt, ipf_tftp_softc_t *);
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if (softt == NULL)
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return NULL;
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bzero((char *)softt, sizeof(*softt));
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softt->ipf_p_tftp_tune = ipf_tune_array_copy(softt,
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sizeof(ipf_tftp_tuneables),
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ipf_tftp_tuneables);
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if (softt->ipf_p_tftp_tune == NULL) {
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ipf_p_tftp_soft_destroy(softc, softt);
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return NULL;
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}
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if (ipf_tune_array_link(softc, softt->ipf_p_tftp_tune) == -1) {
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ipf_p_tftp_soft_destroy(softc, softt);
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return NULL;
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}
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softt->ipf_p_tftp_readonly = 1;
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return softt;
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}
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void
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ipf_p_tftp_soft_destroy(ipf_main_softc_t *softc, void *arg)
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{
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ipf_tftp_softc_t *softt = arg;
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if (softt->ipf_p_tftp_tune != NULL) {
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ipf_tune_array_unlink(softc, softt->ipf_p_tftp_tune);
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KFREES(softt->ipf_p_tftp_tune, sizeof(ipf_tftp_tuneables));
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softt->ipf_p_tftp_tune = NULL;
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}
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KFREE(softt);
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}
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int
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ipf_p_tftp_out(void *arg, fr_info_t *fin, ap_session_t *aps, nat_t *nat)
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{
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ipf_tftp_softc_t *softt = arg;
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fin->fin_flx |= FI_NOWILD;
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if (nat->nat_dir == NAT_OUTBOUND)
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return ipf_p_tftp_client(softt, fin, aps, nat);
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return ipf_p_tftp_server(softt, fin, aps, nat);
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}
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int
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ipf_p_tftp_in(void *arg, fr_info_t *fin, ap_session_t *aps, nat_t *nat)
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{
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ipf_tftp_softc_t *softt = arg;
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fin->fin_flx |= FI_NOWILD;
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if (nat->nat_dir == NAT_INBOUND)
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return ipf_p_tftp_client(softt, fin, aps, nat);
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return ipf_p_tftp_server(softt, fin, aps, nat);
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}
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int
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ipf_p_tftp_new(void *arg, fr_info_t *fin, ap_session_t *aps, nat_t *nat)
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{
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udphdr_t *udp;
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tftpinfo_t *ti;
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ipnat_t *ipn;
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ipnat_t *np;
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int size;
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fin = fin; /* LINT */
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np = nat->nat_ptr;
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size = np->in_size;
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KMALLOC(ti, tftpinfo_t *);
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if (ti == NULL)
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return -1;
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KMALLOCS(ipn, ipnat_t *, size);
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if (ipn == NULL) {
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KFREE(ti);
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return -1;
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}
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aps->aps_data = ti;
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aps->aps_psiz = sizeof(*ti);
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bzero((char *)ti, sizeof(*ti));
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bzero((char *)ipn, size);
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ti->ti_rule = ipn;
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udp = (udphdr_t *)fin->fin_dp;
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aps->aps_sport = udp->uh_sport;
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aps->aps_dport = udp->uh_dport;
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ipn->in_size = size;
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ipn->in_apr = NULL;
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ipn->in_use = 1;
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ipn->in_hits = 1;
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ipn->in_ippip = 1;
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ipn->in_pr[0] = IPPROTO_UDP;
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ipn->in_pr[1] = IPPROTO_UDP;
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ipn->in_ifps[0] = nat->nat_ifps[0];
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ipn->in_ifps[1] = nat->nat_ifps[1];
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ipn->in_v[0] = nat->nat_ptr->in_v[1];
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ipn->in_v[1] = nat->nat_ptr->in_v[0];
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ipn->in_flags = IPN_UDP|IPN_FIXEDDPORT|IPN_PROXYRULE;
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ipn->in_nsrcip6 = nat->nat_odst6;
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ipn->in_osrcip6 = nat->nat_ndst6;
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if ((np->in_redir & NAT_REDIRECT) != 0) {
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ipn->in_redir = NAT_MAP;
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if (ipn->in_v[0] == 4) {
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ipn->in_snip = ntohl(nat->nat_odstaddr);
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ipn->in_dnip = ntohl(nat->nat_nsrcaddr);
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} else {
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#ifdef USE_INET6
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ipn->in_snip6 = nat->nat_odst6;
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ipn->in_dnip6 = nat->nat_nsrc6;
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#endif
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}
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ipn->in_ndstip6 = nat->nat_nsrc6;
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ipn->in_odstip6 = nat->nat_osrc6;
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} else {
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ipn->in_redir = NAT_REDIRECT;
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if (ipn->in_v[0] == 4) {
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ipn->in_snip = ntohl(nat->nat_odstaddr);
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ipn->in_dnip = ntohl(nat->nat_osrcaddr);
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} else {
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#ifdef USE_INET6
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ipn->in_snip6 = nat->nat_odst6;
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ipn->in_dnip6 = nat->nat_osrc6;
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#endif
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}
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ipn->in_ndstip6 = nat->nat_osrc6;
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ipn->in_odstip6 = nat->nat_nsrc6;
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}
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ipn->in_odport = htons(fin->fin_sport);
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ipn->in_ndport = htons(fin->fin_sport);
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IP6_SETONES(&ipn->in_osrcmsk6);
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IP6_SETONES(&ipn->in_nsrcmsk6);
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IP6_SETONES(&ipn->in_odstmsk6);
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IP6_SETONES(&ipn->in_ndstmsk6);
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MUTEX_INIT(&ipn->in_lock, "tftp proxy NAT rule");
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ipn->in_namelen = np->in_namelen;
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bcopy(np->in_names, ipn->in_ifnames, ipn->in_namelen);
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ipn->in_ifnames[0] = np->in_ifnames[0];
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ipn->in_ifnames[1] = np->in_ifnames[1];
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ti->ti_lastcmd = 0;
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return 0;
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}
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void
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ipf_p_tftp_del(ipf_main_softc_t *softc, ap_session_t *aps)
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{
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tftpinfo_t *tftp;
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tftp = aps->aps_data;
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if (tftp != NULL) {
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tftp->ti_rule->in_flags |= IPN_DELETE;
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ipf_nat_rule_deref(softc, &tftp->ti_rule);
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}
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}
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/*
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* Setup for a new TFTP proxy.
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*/
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int
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ipf_p_tftp_backchannel(fr_info_t *fin, ap_session_t *aps, nat_t *nat)
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{
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ipf_main_softc_t *softc = fin->fin_main_soft;
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#ifdef USE_MUTEXES
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ipf_nat_softc_t *softn = softc->ipf_nat_soft;
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#endif
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#ifdef USE_INET6
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i6addr_t swip6, sw2ip6;
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ip6_t *ip6;
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#endif
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struct in_addr swip, sw2ip;
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tftpinfo_t *ti;
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udphdr_t udp;
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fr_info_t fi;
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u_short slen = 0;
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nat_t *nat2 = NULL;
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int nflags;
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ip_t *ip;
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int dir;
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ti = aps->aps_data;
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/*
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* Add skeleton NAT entry for connection which will come back the
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* other way.
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*/
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bcopy((char *)fin, (char *)&fi, sizeof(fi));
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fi.fin_flx |= FI_IGNORE;
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fi.fin_data[1] = 0;
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bzero((char *)&udp, sizeof(udp));
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udp.uh_sport = 0; /* XXX - don't specify remote port */
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udp.uh_dport = ti->ti_rule->in_ndport;
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udp.uh_ulen = htons(sizeof(udp));
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udp.uh_sum = 0;
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fi.fin_fr = &tftpfr;
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fi.fin_dp = (char *)&udp;
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fi.fin_sport = 0;
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fi.fin_dport = ntohs(ti->ti_rule->in_ndport);
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fi.fin_dlen = sizeof(udp);
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fi.fin_plen = fi.fin_hlen + sizeof(udp);
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fi.fin_flx &= FI_LOWTTL|FI_FRAG|FI_TCPUDP|FI_OPTIONS|FI_IGNORE;
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nflags = NAT_SLAVE|IPN_UDP|SI_W_SPORT;
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#ifdef USE_INET6
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ip6 = (ip6_t *)fin->fin_ip;
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#endif
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ip = fin->fin_ip;
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sw2ip.s_addr = 0;
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swip.s_addr = 0;
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fi.fin_src6 = nat->nat_ndst6;
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fi.fin_dst6 = nat->nat_nsrc6;
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if (nat->nat_v[0] == 4) {
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slen = ip->ip_len;
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ip->ip_len = htons(fin->fin_hlen + sizeof(udp));
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swip = ip->ip_src;
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sw2ip = ip->ip_dst;
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ip->ip_src = nat->nat_ndstip;
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ip->ip_dst = nat->nat_nsrcip;
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} else {
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#ifdef USE_INET6
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slen = ip6->ip6_plen;
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ip6->ip6_plen = htons(sizeof(udp));
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swip6.in6 = ip6->ip6_src;
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sw2ip6.in6 = ip6->ip6_dst;
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ip6->ip6_src = nat->nat_ndst6.in6;
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ip6->ip6_dst = nat->nat_nsrc6.in6;
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#endif
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}
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if (nat->nat_dir == NAT_INBOUND) {
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dir = NAT_OUTBOUND;
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fi.fin_out = 1;
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} else {
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dir = NAT_INBOUND;
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fi.fin_out = 0;
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}
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nflags |= NAT_NOTRULEPORT;
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MUTEX_ENTER(&softn->ipf_nat_new);
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if (nat->nat_v[0] == 4)
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nat2 = ipf_nat_add(&fi, ti->ti_rule, NULL, nflags, dir);
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#ifdef USE_INET6
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else
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nat2 = ipf_nat6_add(&fi, ti->ti_rule, NULL, nflags, dir);
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#endif
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MUTEX_EXIT(&softn->ipf_nat_new);
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if (nat2 != NULL) {
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(void) ipf_nat_proto(&fi, nat2, IPN_UDP);
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ipf_nat_update(&fi, nat2);
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fi.fin_ifp = NULL;
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if (ti->ti_rule->in_redir == NAT_MAP) {
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fi.fin_src6 = nat->nat_ndst6;
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fi.fin_dst6 = nat->nat_nsrc6;
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if (nat->nat_v[0] == 4) {
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ip->ip_src = nat->nat_ndstip;
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ip->ip_dst = nat->nat_nsrcip;
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} else {
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#ifdef USE_INET6
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ip6->ip6_src = nat->nat_ndst6.in6;
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ip6->ip6_dst = nat->nat_nsrc6.in6;
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#endif
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}
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} else {
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fi.fin_src6 = nat->nat_odst6;
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fi.fin_dst6 = nat->nat_osrc6;
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if (fin->fin_v == 4) {
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ip->ip_src = nat->nat_odstip;
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ip->ip_dst = nat->nat_osrcip;
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} else {
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#ifdef USE_INET6
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ip6->ip6_src = nat->nat_odst6.in6;
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ip6->ip6_dst = nat->nat_osrc6.in6;
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#endif
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}
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}
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if (ipf_state_add(softc, &fi, NULL, SI_W_SPORT) != 0) {
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ipf_nat_setpending(softc, nat2);
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}
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}
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if (nat->nat_v[0] == 4) {
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ip->ip_len = slen;
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ip->ip_src = swip;
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ip->ip_dst = sw2ip;
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} else {
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#ifdef USE_INET6
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ip6->ip6_plen = slen;
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ip6->ip6_src = swip6.in6;
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ip6->ip6_dst = sw2ip6.in6;
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#endif
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}
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return 0;
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}
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int
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ipf_p_tftp_client(ipf_tftp_softc_t *softt, fr_info_t *fin, ap_session_t *aps,
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nat_t *nat)
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{
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u_char *msg, *s, *t;
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tftpinfo_t *ti;
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u_short opcode;
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udphdr_t *udp;
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int len;
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if (fin->fin_dlen < 4)
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return 0;
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ti = aps->aps_data;
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msg = fin->fin_dp;
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msg += sizeof(udphdr_t);
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opcode = (msg[0] << 8) | msg[1];
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DT3(tftp_cmd, fr_info_t *, fin, int, opcode, nat_t *, nat);
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switch (opcode)
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{
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case TFTP_CMD_WRITE :
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if (softt->ipf_p_tftp_readonly != 0)
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break;
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/* FALLTHROUGH */
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case TFTP_CMD_READ :
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len = fin->fin_dlen - sizeof(*udp) - 2;
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if (len > sizeof(ti->ti_filename) - 1)
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len = sizeof(ti->ti_filename) - 1;
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s = msg + 2;
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for (t = (u_char *)ti->ti_filename; (len > 0); len--, s++) {
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*t++ = *s;
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if (*s == '\0')
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break;
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}
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ipf_p_tftp_backchannel(fin, aps, nat);
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break;
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default :
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return -1;
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}
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ti = aps->aps_data;
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ti->ti_lastcmd = opcode;
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return 0;
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}
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int
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ipf_p_tftp_server(ipf_tftp_softc_t *softt, fr_info_t *fin, ap_session_t *aps,
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nat_t *nat)
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{
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tftpinfo_t *ti;
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u_short opcode;
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u_short arg;
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u_char *msg;
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if (fin->fin_dlen < 4)
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return 0;
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ti = aps->aps_data;
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msg = fin->fin_dp;
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msg += sizeof(udphdr_t);
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arg = (msg[2] << 8) | msg[3];
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opcode = (msg[0] << 8) | msg[1];
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switch (opcode)
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{
|
|
case TFTP_CMD_ACK :
|
|
ti->ti_lastblk = arg;
|
|
break;
|
|
|
|
case TFTP_CMD_ERROR :
|
|
ti->ti_lasterror = arg;
|
|
break;
|
|
|
|
default :
|
|
return -1;
|
|
}
|
|
|
|
ti->ti_lastcmd = opcode;
|
|
return 0;
|
|
}
|