int
masq_ftp_out (struct ip_masq_app *mapp, struct ip_masq *ms, struct sk_buff **skb_p, __u32 maddr)
{
struct sk_buff *skb;
struct iphdr *iph;
struct tcphdr *th;
char *p, *data, *data_limit;
unsigned char p1,p2,p3,p4,p5,p6;
__u32 from;
__u16 port;
struct ip_masq *n_ms;
char buf[24]; /* xxx.xxx.xxx.xxx,ppp,ppp\000 */
unsigned buf_len;
int diff;
skb = *skb_p;
iph = skb->nh.iph;
th = (struct tcphdr *)&(((char *)iph)[iph->ihl*4]);
data = (char *)&th[1];
data_limit = skb->h.raw + skb->len - 18;
if (skb->len >= 6 && (memcmp(data, "PASV\r\n", 6) == 0 || memcmp(data, "pasv\r\n", 6) == 0))
ms->app_data = &masq_ftp_pasv;
while (data < data_limit)
{
if (memcmp(data,"PORT ",5) && memcmp(data,"port ",5))
{
data ++;
continue;
}
p = data+5;
p1 = simple_strtoul(data+5,&data,10);
if (*data!=',')
continue;
p2 = simple_strtoul(data+1,&data,10);
if (*data!=',')
continue;
p3 = simple_strtoul(data+1,&data,10);
if (*data!=',')
continue;
p4 = simple_strtoul(data+1,&data,10);
if (*data!=',')
continue;
p5 = simple_strtoul(data+1,&data,10);
if (*data!=',')
continue;
p6 = simple_strtoul(data+1,&data,10);
if (*data!='\r' && *data!='\n')
continue;
from = (p1<<24) | (p2<<16) | (p3<<8) | p4;
port = (p5<<8) | p6;
IP_MASQ_DEBUG(1-debug, "PORT %X:%X detected\n",from,port);
/*
* Now update or create an masquerade entry for it
*/
IP_MASQ_DEBUG(1-debug, "protocol %d %lX:%X %X:%X\n", iph->protocol, htonl(from), htons(port), iph->daddr, 0);
n_ms = ip_masq_out_get(iph->protocol,
htonl(from), htons(port),
iph->daddr, 0);
if (!n_ms) {
n_ms = ip_masq_new(IPPROTO_TCP,
maddr, 0,
htonl(from), htons(port),
iph->daddr, 0,
IP_MASQ_F_NO_DPORT);
if (n_ms==NULL)
return 0;
ip_masq_control_add(n_ms, ms);
}
/*
* Replace the old PORT with the new one
*/
from = ntohl(n_ms->maddr);
port = ntohs(n_ms->mport);
sprintf(buf,"%d,%d,%d,%d,%d,%d",
from>>24&255,from>>16&255,from>>8&255,from&255,
port>>8&255,port&255);
buf_len = strlen(buf);
IP_MASQ_DEBUG(1-debug, "new PORT %X:%X\n",from,port);
/*
* Calculate required delta-offset to keep TCP happy
*/
diff = buf_len - (data-p);
/*
* No shift.
*/
if (diff==0) {
/*
* simple case, just replace the old PORT cmd
*/
memcpy(p,buf,buf_len);
} else {
*skb_p = ip_masq_skb_replace(skb, GFP_ATOMIC, p, data-p, buf, buf_len);
}
/*
* Move tunnel to listen state
*/
ip_masq_listen(n_ms);
ip_masq_put(n_ms);
return diff;
}
return 0;
}
int
masq_ftp_in (struct ip_masq_app *mapp, struct ip_masq *ms, struct sk_buff **skb_p, __u32 maddr)
{
struct sk_buff *skb;
struct iphdr *iph;
struct tcphdr *th;
char *data, *data_limit;
unsigned char p1,p2,p3,p4,p5,p6;
__u32 to;
__u16 port;
struct ip_masq *n_ms;
if (ms->app_data != &masq_ftp_pasv)
return 0; /* quick exit if no outstanding PASV */
skb = *skb_p;
iph = skb->nh.iph;
th = (struct tcphdr *)&(((char *)iph)[iph->ihl*4]);
data = (char *)&th[1];
data_limit = skb->h.raw + skb->len;
while (data < data_limit && *data != ' ')
++data;
while (data < data_limit && *data == ' ')
++data;
data += 22;
if (data >= data_limit || *data != '(')
return 0;
p1 = simple_strtoul(data+1, &data, 10);
if (data >= data_limit || *data != ',')
return 0;
p2 = simple_strtoul(data+1, &data, 10);
if (data >= data_limit || *data != ',')
return 0;
p3 = simple_strtoul(data+1, &data, 10);
if (data >= data_limit || *data != ',')
return 0;
p4 = simple_strtoul(data+1, &data, 10);
if (data >= data_limit || *data != ',')
return 0;
p5 = simple_strtoul(data+1, &data, 10);
if (data >= data_limit || *data != ',')
return 0;
p6 = simple_strtoul(data+1, &data, 10);
if (data >= data_limit || *data != ')')
return 0;
to = (p1<<24) | (p2<<16) | (p3<<8) | p4;
port = (p5<<8) | p6;
/*
* Now update or create an masquerade entry for it
*/
IP_MASQ_DEBUG(1-debug, "PASV response %lX:%X %X:%X detected\n", ntohl(ms->saddr), 0, to, port);
n_ms = ip_masq_out_get(iph->protocol,
ms->saddr, 0,
htonl(to), htons(port));
if (!n_ms) {
n_ms = ip_masq_new(IPPROTO_TCP,
maddr, 0,
ms->saddr, 0,
htonl(to), htons(port),
IP_MASQ_F_NO_SPORT);
if (n_ms==NULL)
return 0;
ip_masq_control_add(n_ms, ms);
}
#if 0 /* v0.12 state processing */
/*
* keep for a bit longer than tcp_fin, client may not issue open
* to server port before tcp_fin_timeout.
*/
n_ms->timeout = ip_masq_expire->tcp_fin_timeout*3;
#endif
ms->app_data = NULL;
ip_masq_put(n_ms);
return 0; /* no diff required for incoming packets, thank goodness */
}