mirror of
https://github.com/matrix-construct/construct
synced 2024-08-30 21:35:18 +02:00
This is cleaner. Note this was broken out of a much larger piece of work I did, so if there's any problems, I apologise!
226 lines
5.7 KiB
C
226 lines
5.7 KiB
C
/*
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* Charybdis: an advanced ircd
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* ip_cloaking.c: provide user hostname cloaking
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*
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* Written originally by nenolod, altered to use FNV by Elizabeth in 2008
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*/
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#include "stdinc.h"
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#include "modules.h"
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#include "hook.h"
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#include "client.h"
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#include "ircd.h"
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#include "send.h"
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#include "hash.h"
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#include "s_conf.h"
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#include "s_user.h"
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#include "s_serv.h"
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#include "numeric.h"
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static const char ip_cloaking_desc[] = "IP cloaking module that uses user mode +h";
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static int
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_modinit(void)
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{
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/* add the usermode to the available slot */
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user_modes['h'] = find_umode_slot();
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construct_umodebuf();
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return 0;
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}
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static void
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_moddeinit(void)
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{
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/* disable the umode and remove it from the available list */
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user_modes['h'] = 0;
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construct_umodebuf();
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}
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static void check_umode_change(void *data);
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static void check_new_user(void *data);
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mapi_hfn_list_av1 ip_cloaking_hfnlist[] = {
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{ "umode_changed", (hookfn) check_umode_change },
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{ "new_local_user", (hookfn) check_new_user },
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{ NULL, NULL }
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};
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DECLARE_MODULE_AV2(ip_cloaking, _modinit, _moddeinit, NULL, NULL,
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ip_cloaking_hfnlist, NULL, NULL, ip_cloaking_desc);
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static void
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distribute_hostchange(struct Client *client_p, char *newhost)
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{
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if (newhost != client_p->orighost)
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sendto_one_numeric(client_p, RPL_HOSTHIDDEN, "%s :is now your hidden host",
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newhost);
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else
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sendto_one_numeric(client_p, RPL_HOSTHIDDEN, "%s :hostname reset",
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newhost);
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sendto_server(NULL, NULL,
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CAP_EUID | CAP_TS6, NOCAPS, ":%s CHGHOST %s :%s",
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use_id(&me), use_id(client_p), newhost);
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sendto_server(NULL, NULL,
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CAP_TS6, CAP_EUID, ":%s ENCAP * CHGHOST %s :%s",
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use_id(&me), use_id(client_p), newhost);
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change_nick_user_host(client_p, client_p->name, client_p->username, newhost, 0, "Changing host");
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if (newhost != client_p->orighost)
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SetDynSpoof(client_p);
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else
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ClearDynSpoof(client_p);
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}
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static void
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do_host_cloak_ip(const char *inbuf, char *outbuf)
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{
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/* None of the characters in this table can be valid in an IP */
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char chartable[] = "ghijklmnopqrstuvwxyz";
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char *tptr;
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uint32_t accum = fnv_hash((const unsigned char*) inbuf, 32);
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int sepcount = 0;
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int totalcount = 0;
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int ipv6 = 0;
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rb_strlcpy(outbuf, inbuf, HOSTLEN + 1);
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if (strchr(outbuf, ':'))
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{
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ipv6 = 1;
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/* Damn you IPv6...
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* We count the number of colons so we can calculate how much
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* of the host to cloak. This is because some hostmasks may not
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* have as many octets as we'd like.
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*
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* We have to do this ahead of time because doing this during
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* the actual cloaking would get ugly
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*/
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for (tptr = outbuf; *tptr != '\0'; tptr++)
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if (*tptr == ':')
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totalcount++;
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}
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else if (!strchr(outbuf, '.'))
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return;
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for (tptr = outbuf; *tptr != '\0'; tptr++)
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{
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if (*tptr == ':' || *tptr == '.')
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{
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sepcount++;
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continue;
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}
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if (ipv6 && sepcount < totalcount / 2)
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continue;
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if (!ipv6 && sepcount < 2)
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continue;
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*tptr = chartable[(*tptr + accum) % 20];
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accum = (accum << 1) | (accum >> 31);
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}
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}
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static void
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do_host_cloak_host(const char *inbuf, char *outbuf)
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{
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char b26_alphabet[] = "abcdefghijklmnopqrstuvwxyz";
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char *tptr;
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uint32_t accum = fnv_hash((const unsigned char*) inbuf, 32);
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rb_strlcpy(outbuf, inbuf, HOSTLEN + 1);
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/* pass 1: scramble first section of hostname using base26
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* alphabet toasted against the FNV hash of the string.
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*
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* numbers are not changed at this time, only letters.
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*/
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for (tptr = outbuf; *tptr != '\0'; tptr++)
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{
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if (*tptr == '.')
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break;
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if (isdigit((unsigned char)*tptr) || *tptr == '-')
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continue;
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*tptr = b26_alphabet[(*tptr + accum) % 26];
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/* Rotate one bit to avoid all digits being turned odd or even */
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accum = (accum << 1) | (accum >> 31);
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}
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/* pass 2: scramble each number in the address */
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for (tptr = outbuf; *tptr != '\0'; tptr++)
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{
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if (isdigit((unsigned char)*tptr))
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*tptr = '0' + (*tptr + accum) % 10;
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accum = (accum << 1) | (accum >> 31);
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}
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}
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static void
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check_umode_change(void *vdata)
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{
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hook_data_umode_changed *data = (hook_data_umode_changed *)vdata;
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struct Client *source_p = data->client;
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if (!MyClient(source_p))
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return;
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/* didn't change +h umode, we don't need to do anything */
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if (!((data->oldumodes ^ source_p->umodes) & user_modes['h']))
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return;
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if (source_p->umodes & user_modes['h'])
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{
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if (IsIPSpoof(source_p) || source_p->localClient->mangledhost == NULL || (IsDynSpoof(source_p) && strcmp(source_p->host, source_p->localClient->mangledhost)))
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{
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source_p->umodes &= ~user_modes['h'];
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return;
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}
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if (strcmp(source_p->host, source_p->localClient->mangledhost))
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{
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distribute_hostchange(source_p, source_p->localClient->mangledhost);
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}
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else /* not really nice, but we need to send this numeric here */
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sendto_one_numeric(source_p, RPL_HOSTHIDDEN, "%s :is now your hidden host",
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source_p->host);
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}
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else if (!(source_p->umodes & user_modes['h']))
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{
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if (source_p->localClient->mangledhost != NULL &&
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!strcmp(source_p->host, source_p->localClient->mangledhost))
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{
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distribute_hostchange(source_p, source_p->orighost);
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}
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}
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}
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static void
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check_new_user(void *vdata)
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{
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struct Client *source_p = (void *)vdata;
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if (IsIPSpoof(source_p))
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{
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source_p->umodes &= ~user_modes['h'];
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return;
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}
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source_p->localClient->mangledhost = rb_malloc(HOSTLEN + 1);
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if (!irccmp(source_p->orighost, source_p->sockhost))
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do_host_cloak_ip(source_p->orighost, source_p->localClient->mangledhost);
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else
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do_host_cloak_host(source_p->orighost, source_p->localClient->mangledhost);
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if (IsDynSpoof(source_p))
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source_p->umodes &= ~user_modes['h'];
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if (source_p->umodes & user_modes['h'])
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{
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rb_strlcpy(source_p->host, source_p->localClient->mangledhost, sizeof(source_p->host));
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if (irccmp(source_p->host, source_p->orighost))
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SetDynSpoof(source_p);
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}
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}
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