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authorWilliam Allen Simpson <william.allen.simpson@gmail.com>2009-12-02 18:19:30 +0000
committerDavid S. Miller <davem@davemloft.net>2009-12-02 22:07:25 -0800
commite56fb50f2b7958b931c8a2fc0966061b3f3c8f3a (patch)
tree392f548e99f5d098286cea54fb9e18ac8c31e672 /net
parentTCPCT part 1d: define TCP cookie option, extend existing struct's (diff)
downloadlinux-dev-e56fb50f2b7958b931c8a2fc0966061b3f3c8f3a.tar.xz
linux-dev-e56fb50f2b7958b931c8a2fc0966061b3f3c8f3a.zip
TCPCT part 1e: implement socket option TCP_COOKIE_TRANSACTIONS
Provide per socket control of the TCP cookie option and SYN/SYNACK data. This is a straightforward re-implementation of an earlier (year-old) patch that no longer applies cleanly, with permission of the original author (Adam Langley): http://thread.gmane.org/gmane.linux.network/102586 The principle difference is using a TCP option to carry the cookie nonce, instead of a user configured offset in the data. Allocations have been rearranged to avoid requiring GFP_ATOMIC. Requires: net: TCP_MSS_DEFAULT, TCP_MSS_DESIRED TCPCT part 1c: sysctl_tcp_cookie_size, socket option TCP_COOKIE_TRANSACTIONS TCPCT part 1d: define TCP cookie option, extend existing struct's Signed-off-by: William.Allen.Simpson@gmail.com Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net')
-rw-r--r--net/ipv4/tcp.c133
1 files changed, 131 insertions, 2 deletions
diff --git a/net/ipv4/tcp.c b/net/ipv4/tcp.c
index ba03ac80435a..c8666b70cde0 100644
--- a/net/ipv4/tcp.c
+++ b/net/ipv4/tcp.c
@@ -2085,8 +2085,9 @@ static int do_tcp_setsockopt(struct sock *sk, int level,
int val;
int err = 0;
- /* This is a string value all the others are int's */
- if (optname == TCP_CONGESTION) {
+ /* These are data/string values, all the others are ints */
+ switch (optname) {
+ case TCP_CONGESTION: {
char name[TCP_CA_NAME_MAX];
if (optlen < 1)
@@ -2103,6 +2104,93 @@ static int do_tcp_setsockopt(struct sock *sk, int level,
release_sock(sk);
return err;
}
+ case TCP_COOKIE_TRANSACTIONS: {
+ struct tcp_cookie_transactions ctd;
+ struct tcp_cookie_values *cvp = NULL;
+
+ if (sizeof(ctd) > optlen)
+ return -EINVAL;
+ if (copy_from_user(&ctd, optval, sizeof(ctd)))
+ return -EFAULT;
+
+ if (ctd.tcpct_used > sizeof(ctd.tcpct_value) ||
+ ctd.tcpct_s_data_desired > TCP_MSS_DESIRED)
+ return -EINVAL;
+
+ if (ctd.tcpct_cookie_desired == 0) {
+ /* default to global value */
+ } else if ((0x1 & ctd.tcpct_cookie_desired) ||
+ ctd.tcpct_cookie_desired > TCP_COOKIE_MAX ||
+ ctd.tcpct_cookie_desired < TCP_COOKIE_MIN) {
+ return -EINVAL;
+ }
+
+ if (TCP_COOKIE_OUT_NEVER & ctd.tcpct_flags) {
+ /* Supercedes all other values */
+ lock_sock(sk);
+ if (tp->cookie_values != NULL) {
+ kref_put(&tp->cookie_values->kref,
+ tcp_cookie_values_release);
+ tp->cookie_values = NULL;
+ }
+ tp->rx_opt.cookie_in_always = 0; /* false */
+ tp->rx_opt.cookie_out_never = 1; /* true */
+ release_sock(sk);
+ return err;
+ }
+
+ /* Allocate ancillary memory before locking.
+ */
+ if (ctd.tcpct_used > 0 ||
+ (tp->cookie_values == NULL &&
+ (sysctl_tcp_cookie_size > 0 ||
+ ctd.tcpct_cookie_desired > 0 ||
+ ctd.tcpct_s_data_desired > 0))) {
+ cvp = kzalloc(sizeof(*cvp) + ctd.tcpct_used,
+ GFP_KERNEL);
+ if (cvp == NULL)
+ return -ENOMEM;
+ }
+ lock_sock(sk);
+ tp->rx_opt.cookie_in_always =
+ (TCP_COOKIE_IN_ALWAYS & ctd.tcpct_flags);
+ tp->rx_opt.cookie_out_never = 0; /* false */
+
+ if (tp->cookie_values != NULL) {
+ if (cvp != NULL) {
+ /* Changed values are recorded by a changed
+ * pointer, ensuring the cookie will differ,
+ * without separately hashing each value later.
+ */
+ kref_put(&tp->cookie_values->kref,
+ tcp_cookie_values_release);
+ kref_init(&cvp->kref);
+ tp->cookie_values = cvp;
+ } else {
+ cvp = tp->cookie_values;
+ }
+ }
+ if (cvp != NULL) {
+ cvp->cookie_desired = ctd.tcpct_cookie_desired;
+
+ if (ctd.tcpct_used > 0) {
+ memcpy(cvp->s_data_payload, ctd.tcpct_value,
+ ctd.tcpct_used);
+ cvp->s_data_desired = ctd.tcpct_used;
+ cvp->s_data_constant = 1; /* true */
+ } else {
+ /* No constant payload data. */
+ cvp->s_data_desired = ctd.tcpct_s_data_desired;
+ cvp->s_data_constant = 0; /* false */
+ }
+ }
+ release_sock(sk);
+ return err;
+ }
+ default:
+ /* fallthru */
+ break;
+ };
if (optlen < sizeof(int))
return -EINVAL;
@@ -2427,6 +2515,47 @@ static int do_tcp_getsockopt(struct sock *sk, int level,
if (copy_to_user(optval, icsk->icsk_ca_ops->name, len))
return -EFAULT;
return 0;
+
+ case TCP_COOKIE_TRANSACTIONS: {
+ struct tcp_cookie_transactions ctd;
+ struct tcp_cookie_values *cvp = tp->cookie_values;
+
+ if (get_user(len, optlen))
+ return -EFAULT;
+ if (len < sizeof(ctd))
+ return -EINVAL;
+
+ memset(&ctd, 0, sizeof(ctd));
+ ctd.tcpct_flags = (tp->rx_opt.cookie_in_always ?
+ TCP_COOKIE_IN_ALWAYS : 0)
+ | (tp->rx_opt.cookie_out_never ?
+ TCP_COOKIE_OUT_NEVER : 0);
+
+ if (cvp != NULL) {
+ ctd.tcpct_flags |= (cvp->s_data_in ?
+ TCP_S_DATA_IN : 0)
+ | (cvp->s_data_out ?
+ TCP_S_DATA_OUT : 0);
+
+ ctd.tcpct_cookie_desired = cvp->cookie_desired;
+ ctd.tcpct_s_data_desired = cvp->s_data_desired;
+
+ /* Cookie(s) saved, return as nonce */
+ if (sizeof(ctd.tcpct_value) < cvp->cookie_pair_size) {
+ /* impossible? */
+ return -EINVAL;
+ }
+ memcpy(&ctd.tcpct_value[0], &cvp->cookie_pair[0],
+ cvp->cookie_pair_size);
+ ctd.tcpct_used = cvp->cookie_pair_size;
+ }
+
+ if (put_user(sizeof(ctd), optlen))
+ return -EFAULT;
+ if (copy_to_user(optval, &ctd, sizeof(ctd)))
+ return -EFAULT;
+ return 0;
+ }
default:
return -ENOPROTOOPT;
}