/* FIXME: Examine ipfilter's timeouts and conntrack transitions more
closely. They're more complex. --RR */
-static const char *tcp_conntrack_names[] = {
+static const char *const tcp_conntrack_names[] = {
"NONE",
"SYN_SENT",
"SYN_RECV",
* CLOSE_WAIT: ACK seen (after FIN)
* LAST_ACK: FIN seen (after FIN)
* TIME_WAIT: last ACK seen
- * CLOSE: closed connection
+ * CLOSE: closed connection (RST)
*
* LISTEN state is not used.
*
unsigned int dataoff,
struct nf_conntrack_tuple *tuple)
{
- struct tcphdr _hdr, *hp;
+ const struct tcphdr *hp;
+ struct tcphdr _hdr;
/* Actually only need first 8 bytes. */
hp = skb_header_pointer(skb, dataoff, 8, &_hdr);
static inline __u32 segment_seq_plus_len(__u32 seq,
size_t len,
unsigned int dataoff,
- struct tcphdr *tcph)
+ const struct tcphdr *tcph)
{
/* XXX Should I use payload length field in IP/IPv6 header ?
* - YK */
*/
static void tcp_options(const struct sk_buff *skb,
unsigned int dataoff,
- struct tcphdr *tcph,
+ const struct tcphdr *tcph,
struct ip_ct_tcp_state *state)
{
unsigned char buff[(15 * 4) - sizeof(struct tcphdr)];
- unsigned char *ptr;
+ const unsigned char *ptr;
int length = (tcph->doff*4) - sizeof(struct tcphdr);
if (!length)
}
static void tcp_sack(const struct sk_buff *skb, unsigned int dataoff,
- struct tcphdr *tcph, __u32 *sack)
+ const struct tcphdr *tcph, __u32 *sack)
{
unsigned char buff[(15 * 4) - sizeof(struct tcphdr)];
- unsigned char *ptr;
+ const unsigned char *ptr;
int length = (tcph->doff*4) - sizeof(struct tcphdr);
__u32 tmp;
}
}
-static int tcp_in_window(struct nf_conn *ct,
+static int tcp_in_window(const struct nf_conn *ct,
struct ip_ct_tcp *state,
enum ip_conntrack_dir dir,
unsigned int index,
const struct sk_buff *skb,
unsigned int dataoff,
- struct tcphdr *tcph,
+ const struct tcphdr *tcph,
int pf)
{
struct ip_ct_tcp_state *sender = &state->seen[dir];
struct ip_ct_tcp_state *receiver = &state->seen[!dir];
- struct nf_conntrack_tuple *tuple = &ct->tuplehash[dir].tuple;
+ const struct nf_conntrack_tuple *tuple = &ct->tuplehash[dir].tuple;
__u32 seq, ack, sack, end, win, swin;
int res;
#ifdef CONFIG_NF_NAT_NEEDED
/* Update sender->td_end after NAT successfully mangled the packet */
/* Caller must linearize skb at tcp header. */
-void nf_conntrack_tcp_update(struct sk_buff *skb,
+void nf_conntrack_tcp_update(const struct sk_buff *skb,
unsigned int dataoff,
struct nf_conn *ct,
int dir)
{
- struct tcphdr *tcph = (void *)skb->data + dataoff;
- struct ip_ct_tcp_state *sender = &ct->proto.tcp.seen[dir];
- struct ip_ct_tcp_state *receiver = &ct->proto.tcp.seen[!dir];
+ const struct tcphdr *tcph = (const void *)skb->data + dataoff;
+ const struct ip_ct_tcp_state *sender = &ct->proto.tcp.seen[dir];
+ const struct ip_ct_tcp_state *receiver = &ct->proto.tcp.seen[!dir];
__u32 end;
end = segment_seq_plus_len(ntohl(tcph->seq), skb->len, dataoff, tcph);
#define TH_CWR 0x80
/* table of valid flag combinations - PUSH, ECE and CWR are always valid */
-static u8 tcp_valid_flags[(TH_FIN|TH_SYN|TH_RST|TH_ACK|TH_URG) + 1] =
+static const u8 tcp_valid_flags[(TH_FIN|TH_SYN|TH_RST|TH_ACK|TH_URG) + 1] =
{
[TH_SYN] = 1,
[TH_SYN|TH_URG] = 1,
int pf,
unsigned int hooknum)
{
- struct tcphdr _tcph, *th;
+ const struct tcphdr *th;
+ struct tcphdr _tcph;
unsigned int tcplen = skb->len - dataoff;
u_int8_t tcpflags;
struct nf_conntrack_tuple *tuple;
enum tcp_conntrack new_state, old_state;
enum ip_conntrack_dir dir;
- struct tcphdr *th, _tcph;
+ const struct tcphdr *th;
+ struct tcphdr _tcph;
unsigned long timeout;
unsigned int index;
case TCP_CONNTRACK_SYN_SENT:
if (old_state < TCP_CONNTRACK_TIME_WAIT)
break;
- if ((ct->proto.tcp.seen[!dir].flags & IP_CT_TCP_FLAG_CLOSE_INIT)
+ /* RFC 1122: "When a connection is closed actively,
+ * it MUST linger in TIME-WAIT state for a time 2xMSL
+ * (Maximum Segment Lifetime). However, it MAY accept
+ * a new SYN from the remote TCP to reopen the connection
+ * directly from TIME-WAIT state, if..."
+ * We ignore the conditions because we are in the
+ * TIME-WAIT state anyway.
+ *
+ * Handle aborted connections: we and the server
+ * think there is an existing connection but the client
+ * aborts it and starts a new one.
+ */
+ if (((ct->proto.tcp.seen[dir].flags
+ | ct->proto.tcp.seen[!dir].flags)
+ & IP_CT_TCP_FLAG_CLOSE_INIT)
|| (ct->proto.tcp.last_dir == dir
&& ct->proto.tcp.last_index == TCP_RST_SET)) {
/* Attempt to reopen a closed/aborted connection.
/* Fall through */
case TCP_CONNTRACK_IGNORE:
/* Ignored packets:
+ *
+ * Our connection entry may be out of sync, so ignore
+ * packets which may signal the real connection between
+ * the client and the server.
*
* a) SYN in ORIGINAL
* b) SYN/ACK in REPLY
* c) ACK in reply direction after initial SYN in original.
+ *
+ * If the ignored packet is invalid, the receiver will send
+ * a RST we'll catch below.
*/
if (index == TCP_SYNACK_SET
&& ct->proto.tcp.last_index == TCP_SYN_SET
&& ct->proto.tcp.last_dir != dir
&& ntohl(th->ack_seq) == ct->proto.tcp.last_end) {
- /* This SYN/ACK acknowledges a SYN that we earlier
+ /* b) This SYN/ACK acknowledges a SYN that we earlier
* ignored as invalid. This means that the client and
* the server are both in sync, while the firewall is
* not. We kill this session and block the SYN/ACK so
write_unlock_bh(&tcp_lock);
if (LOG_INVALID(IPPROTO_TCP))
nf_log_packet(pf, 0, skb, NULL, NULL, NULL,
- "nf_ct_tcp: invalid packed ignored ");
+ "nf_ct_tcp: invalid packet ignored ");
return NF_ACCEPT;
case TCP_CONNTRACK_MAX:
/* Invalid packet */
ct->proto.tcp.state = new_state;
if (old_state != new_state
- && (new_state == TCP_CONNTRACK_FIN_WAIT
- || new_state == TCP_CONNTRACK_CLOSE))
+ && new_state == TCP_CONNTRACK_CLOSE)
ct->proto.tcp.seen[dir].flags |= IP_CT_TCP_FLAG_CLOSE_INIT;
timeout = ct->proto.tcp.retrans >= nf_ct_tcp_max_retrans
&& tcp_timeouts[new_state] > nf_ct_tcp_timeout_max_retrans
unsigned int dataoff)
{
enum tcp_conntrack new_state;
- struct tcphdr *th, _tcph;
- struct ip_ct_tcp_state *sender = &ct->proto.tcp.seen[0];
- struct ip_ct_tcp_state *receiver = &ct->proto.tcp.seen[1];
+ const struct tcphdr *th;
+ struct tcphdr _tcph;
+ const struct ip_ct_tcp_state *sender = &ct->proto.tcp.seen[0];
+ const struct ip_ct_tcp_state *receiver = &ct->proto.tcp.seen[1];
th = skb_header_pointer(skb, dataoff, sizeof(_tcph), &_tcph);
BUG_ON(th == NULL);
projects / linux-2.6-omap-h63xx.git / blobdiff