On Sat, 10 Jul 2010 16:55:21 +0800
Pete Kay <petedao@xxxxxxxxx> wrote:
> Hi,
>
> I am trying to write some code to simulate this iptables rule:
> iptables -append -t nat -A PREROUTING -s 192.168.3.2 -p udp --dport 80
> -j ACCEPT
>
iptables -t nat -A PREROUTING -s 192.168.3.2 -p udp --dport 80 -j ACCEPT
There is no -append option or at least there isn't on my version.
> But I am getting "Invalid Argument" error when running the commit.
> Does anyone know what could be wrong with my sample code here?
>
> Any help will be greatly appreciated.
>
> struct ipt_entry *e=NULL;
> struct ipt_entry_target *pt;
> struct ipt_entry_match *pm;
> struct ipt_udp *pudp;
> const char *tablename = "nat";
> iptc_handle_t h = iptc_init(tablename);
> int ret = 0;
> size_t target_size, match_size, size;
> match_size = sizeof(struct ipt_entry_match) + sizeof(struct ipt_tcp);
> target_size = IPT_ALIGN(sizeof(struct ipt_entry_target)) +
> IPT_ALIGN(sizeof(int));
> size = sizeof(*e) + match_size + target_size;
> e = calloc(1, size);
> e->ip.src.s_addr = inet_addr("192.168.3.2");
> e->ip.smsk.s_addr = -1;
> e->ip.proto = IPPROTO_UDP;
> e->target_offset = sizeof(*e) + match_size;
> e->next_offset = size;
> pm = (struct ipt_entry_match *)e->elems;
> pm->u.user.match_size = match_size;
> strcpy(pm->u.user.name, "udp");
> pudp = (struct ipt_udp*)pm->data;
> pudp->spts[0] = 0;
> pudp->spts[1] = 0;
> pudp->dpts[0] = 80;
> pudp->dpts[1] = 0xffff;
>
> pt = (struct ipt_entry_target *) (e->elems + match_size);
> pt->u.user.target_size = target_size;
> strcpy(pt->u.user.name, "ACCEPT");
> if ( !h ) { printf("Error initializing:
> %s\n", iptc_strerror(errno));
> }
> ret = iptc_append_entry("PREROUTING", e, h);
> printf("append = [%i]\n", ret);
> ret = iptc_commit(h);
> printf("commit = [%i]\n",ret);
> if (!ret) {
> printf("false : %s\n", iptc_strerror(errno)); }
>
>
>
> Thanks,
> P
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--
Jeff Largent <jwlargent@xxxxxxxxxxx>
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