From: Peter Krystad <peter.krys...@linux.intel.com>
Subflow creation may be initiated by the path manager when
the primary connection is fully established and a remote
address has been received via ADD_ADDR.
Create an in-kernel sock and use kernel_connect() to
initiate connection. When a valid SYN-ACK is received the
new sock is added to the tail of the mptcp sock conn_list
where it will not interfere with data flow on the original
connection.
Data flow and connection failover not addressed by this commit.
Signed-off-by: Peter Krystad <peter.krys...@linux.intel.com>
Signed-off-by: Florian Westphal <f...@strlen.de>
---
include/net/mptcp.h | 2 +
net/mptcp/options.c | 51 +++++++++++++++++++++--
net/mptcp/protocol.c | 1 +
net/mptcp/protocol.h | 9 ++++
net/mptcp/subflow.c | 98 +++++++++++++++++++++++++++++++++++++++++++-
5 files changed, 156 insertions(+), 5 deletions(-)
diff --git a/include/net/mptcp.h b/include/net/mptcp.h
index bb2dd193c0c5..50cd1b31ebdd 100644
--- a/include/net/mptcp.h
+++ b/include/net/mptcp.h
@@ -40,6 +40,8 @@ struct mptcp_out_options {
u8 backup;
u32 nonce;
u64 thmac;
+ u32 token;
+ u8 hmac[20];
struct mptcp_ext ext_copy;
#endif
};
diff --git a/net/mptcp/options.c b/net/mptcp/options.c
index f5e0b1d0931b..ce298ecc64f5 100644
--- a/net/mptcp/options.c
+++ b/net/mptcp/options.c
@@ -316,6 +316,16 @@ bool mptcp_syn_options(struct sock *sk, unsigned int *size,
opts->sndr_key = subflow->local_key;
*size = TCPOLEN_MPTCP_MPC_SYN;
return true;
+ } else if (subflow->request_join) {
+ pr_debug("remote_token=%u, nonce=%u", subflow->remote_token,
+ subflow->local_nonce);
+ opts->suboptions = OPTION_MPTCP_MPJ_SYN;
+ opts->join_id = subflow->remote_id;
+ opts->token = subflow->remote_token;
+ opts->nonce = subflow->local_nonce;
+ opts->backup = subflow->request_bkup;
+ *size = TCPOLEN_MPTCP_MPJ_SYN;
+ return true;
}
return false;
}
@@ -325,10 +335,17 @@ void mptcp_rcv_synsent(struct sock *sk)
struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(sk);
struct tcp_sock *tp = tcp_sk(sk);
- pr_debug("subflow=%p", subflow);
if (subflow->request_mptcp && tp->rx_opt.mptcp.mp_capable) {
subflow->mp_capable = 1;
subflow->remote_key = tp->rx_opt.mptcp.sndr_key;
+ pr_debug("subflow=%p, remote_key=%llu", subflow,
+ subflow->remote_key);
+ } else if (subflow->request_join && tp->rx_opt.mptcp.mp_join) {
+ subflow->mp_join = 1;
+ subflow->thmac = tp->rx_opt.mptcp.thmac;
+ subflow->remote_nonce = tp->rx_opt.mptcp.nonce;
+ pr_debug("subflow=%p, thmac=%llu, remote_nonce=%u", subflow,
+ subflow->thmac, subflow->remote_nonce);
}
}
@@ -338,7 +355,8 @@ static bool mptcp_established_options_mp(struct sock *sk,
unsigned int *size,
{
struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(sk);
- if (!subflow->fourth_ack && remaining >= TCPOLEN_MPTCP_MPC_ACK) {
+ if (subflow->mp_capable && !subflow->fourth_ack &&
+ remaining >= TCPOLEN_MPTCP_MPC_ACK) {
opts->suboptions = OPTION_MPTCP_MPC_ACK;
opts->sndr_key = subflow->local_key;
opts->rcvr_key = subflow->remote_key;
@@ -347,6 +365,14 @@ static bool mptcp_established_options_mp(struct sock *sk,
unsigned int *size,
pr_debug("subflow=%p, local_key=%llu, remote_key=%llu",
subflow, subflow->local_key, subflow->remote_key);
return true;
+ } else if (subflow->mp_join && !subflow->fourth_ack &&
+ remaining >= TCPOLEN_MPTCP_MPJ_ACK) {
+ opts->suboptions = OPTION_MPTCP_MPJ_ACK;
+ memcpy(opts->hmac, subflow->hmac, MPTCPOPT_HMAC_LEN);
+ *size = TCPOLEN_MPTCP_MPJ_ACK;
+ subflow->fourth_ack = 1;
+ pr_debug("subflow=%p", subflow);
+ return true;
}
return false;
}
@@ -459,10 +485,11 @@ bool mptcp_established_options(struct sock *sk, struct
sk_buff *skb,
unsigned int *size, unsigned int remaining,
struct mptcp_out_options *opts)
{
+ struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(sk);
unsigned int opt_size = 0;
bool ret = false;
- if (!mptcp_subflow_ctx(sk)->mp_capable)
+ if (!subflow->mp_capable && !subflow->mp_join)
return false;
opts->suboptions = 0;
@@ -562,7 +589,6 @@ void mptcp_incoming_options(struct sock *sk, struct sk_buff
*skb,
if (msk)
pm_fully_established(msk);
-
}
void mptcp_write_options(__be32 *ptr, struct mptcp_out_options *opts)
@@ -612,6 +638,16 @@ void mptcp_write_options(__be32 *ptr, struct
mptcp_out_options *opts)
0, opts->addr_id);
}
+ if (OPTION_MPTCP_MPJ_SYN & opts->suboptions) {
+ *ptr++ = mptcp_option(MPTCPOPT_MP_JOIN,
+ TCPOLEN_MPTCP_MPJ_SYN,
+ opts->backup, opts->join_id);
+ put_unaligned_be32(opts->token, ptr);
+ ptr += 1;
+ put_unaligned_be32(opts->nonce, ptr);
+ ptr += 1;
+ }
+
if (OPTION_MPTCP_MPJ_SYNACK & opts->suboptions) {
*ptr++ = mptcp_option(MPTCPOPT_MP_JOIN,
TCPOLEN_MPTCP_MPJ_SYNACK,
@@ -622,6 +658,13 @@ void mptcp_write_options(__be32 *ptr, struct
mptcp_out_options *opts)
ptr += 1;
}
+ if (OPTION_MPTCP_MPJ_ACK & opts->suboptions) {
+ *ptr++ = mptcp_option(MPTCPOPT_MP_JOIN,
+ TCPOLEN_MPTCP_MPJ_ACK, 0, 0);
+ memcpy(ptr, opts->hmac, MPTCPOPT_HMAC_LEN);
+ ptr += 5;
+ }
+
if (opts->ext_copy.use_ack || opts->ext_copy.use_map) {
struct mptcp_ext *mpext = &opts->ext_copy;
u8 len = TCPOLEN_MPTCP_DSS_BASE;
diff --git a/net/mptcp/protocol.c b/net/mptcp/protocol.c
index fa99337ca773..445800eae767 100644
--- a/net/mptcp/protocol.c
+++ b/net/mptcp/protocol.c
@@ -787,6 +787,7 @@ void mptcp_finish_connect(struct sock *sk, int mp_capable)
msk->local_key = subflow->local_key;
msk->token = subflow->token;
pr_debug("msk=%p, token=%u", msk, msk->token);
+ msk->dport = ntohs(inet_sk(msk->subflow->sk)->inet_dport);
pm_new_connection(msk, 0);
diff --git a/net/mptcp/protocol.h b/net/mptcp/protocol.h
index 394f2477e6f8..4a1171b75ec6 100644
--- a/net/mptcp/protocol.h
+++ b/net/mptcp/protocol.h
@@ -49,8 +49,10 @@
#define TCPOLEN_MPTCP_ADD_ADDR6 20
#define TCPOLEN_MPTCP_RM_ADDR 4
+/* MPTCP MP_JOIN flags */
#define MPTCPOPT_BACKUP BIT(0)
#define MPTCPOPT_HMAC_LEN 20
+#define MPTCPOPT_THMAC_LEN 8
/* MPTCP MP_CAPABLE flags */
#define MPTCP_VERSION_MASK (0x0F)
@@ -115,6 +117,7 @@ struct mptcp_sock {
u64 write_seq;
u64 ack_seq;
u32 token;
+ u16 dport;
struct list_head conn_list;
struct socket *subflow; /* outgoing connect/listener/!mp_capable */
struct mptcp_pm_data pm;
@@ -167,7 +170,9 @@ struct mptcp_subflow_context {
u32 ssn_offset;
u16 map_data_len;
u16 request_mptcp : 1, /* send MP_CAPABLE */
+ request_join : 1, /* send MP_JOIN */
request_cksum : 1,
+ request_bkup : 1,
request_version : 4,
mp_capable : 1, /* remote is MPTCP capable */
mp_join : 1, /* remote is JOINing */
@@ -179,6 +184,8 @@ struct mptcp_subflow_context {
u32 remote_nonce;
u64 thmac;
u32 local_nonce;
+ u32 remote_token;
+ u8 hmac[MPTCPOPT_HMAC_LEN];
u8 local_id;
u8 remote_id;
@@ -207,6 +214,8 @@ mptcp_subflow_tcp_socket(const struct mptcp_subflow_context
*subflow)
int mptcp_is_enabled(struct net *net);
void mptcp_subflow_init(void);
+int mptcp_subflow_connect(struct sock *sk, struct sockaddr_in *local,
+ struct sockaddr_in *remote, u8 remote_id);
int mptcp_subflow_create_socket(struct sock *sk, struct socket **new_sock);
extern const struct inet_connection_sock_af_ops ipv4_specific;
diff --git a/net/mptcp/subflow.c b/net/mptcp/subflow.c
index 04f232ff1df0..257e52d9595e 100644
--- a/net/mptcp/subflow.c
+++ b/net/mptcp/subflow.c
@@ -26,6 +26,13 @@ static int subflow_rebuild_header(struct sock *sk)
if (subflow->request_mptcp && !subflow->token) {
pr_debug("subflow=%p", sk);
err = mptcp_token_new_connect(sk);
+ } else if (subflow->request_join && !subflow->local_nonce) {
+ pr_debug("subflow=%p", sk);
+ mptcp_token_get_sock(subflow->token);
+
+ do {
+ get_random_bytes(&subflow->local_nonce, sizeof(u32));
+ } while (!subflow->local_nonce);
}
if (err)
@@ -130,13 +137,35 @@ static void subflow_v4_init_req(struct request_sock *req,
}
}
+/* validate received truncated hmac and create hmac for third ACK */
+static bool subflow_thmac_valid(struct mptcp_subflow_context *subflow)
+{
+ u8 hmac[MPTCPOPT_HMAC_LEN];
+ u64 thmac;
+
+ mptcp_crypto_hmac_sha1(subflow->remote_key, subflow->local_key,
+ subflow->remote_nonce, subflow->local_nonce,
+ (u32 *)hmac);
+
+ thmac = get_unaligned_be64(hmac);
+ pr_debug("subflow=%p, token=%u, thmac=%llu, subflow->thmac=%llu\n",
+ subflow, subflow->token,
+ (unsigned long long)thmac,
+ (unsigned long long)subflow->thmac);
+
+ return thmac == subflow->thmac;
+}
+
static void subflow_finish_connect(struct sock *sk, const struct sk_buff *skb)
{
struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(sk);
inet_sk_rx_dst_set(sk, skb);
- if (subflow->conn && !subflow->conn_finished) {
+ if (!subflow->conn)
+ return;
+
+ if (subflow->mp_capable && !subflow->conn_finished) {
pr_debug("subflow=%p, remote_key=%llu", mptcp_subflow_ctx(sk),
subflow->remote_key);
mptcp_finish_connect(subflow->conn, subflow->mp_capable);
@@ -146,6 +175,23 @@ static void subflow_finish_connect(struct sock *sk, const
struct sk_buff *skb)
pr_debug("synack seq=%u", TCP_SKB_CB(skb)->seq);
subflow->ssn_offset = TCP_SKB_CB(skb)->seq;
}
+ } else if (subflow->mp_join && !subflow->conn_finished) {
+ pr_debug("subflow=%p, thmac=%llu, remote_nonce=%u",
+ subflow, subflow->thmac,
+ subflow->remote_nonce);
+ if (!subflow_thmac_valid(subflow)) {
+ subflow->mp_join = 0;
+ // @@ need to trigger RST
+ return;
+ }
+
+ mptcp_crypto_hmac_sha1(subflow->local_key, subflow->remote_key,
+ subflow->local_nonce,
+ subflow->remote_nonce,
+ (u32 *)subflow->hmac);
+
+ mptcp_finish_join(sk);
+ subflow->conn_finished = 1;
}
}
@@ -269,6 +315,56 @@ static void subflow_data_ready(struct sock *sk)
}
}
+int mptcp_subflow_connect(struct sock *sk, struct sockaddr_in *local,
+ struct sockaddr_in *remote, u8 remote_id)
+{
+ struct mptcp_sock *msk = mptcp_sk(sk);
+ struct mptcp_subflow_context *subflow;
+ struct socket *sf;
+ u32 remote_token;
+ int err;
+
+ lock_sock(sk);
+ err = mptcp_subflow_create_socket(sk, &sf);
+ if (err) {
+ release_sock(sk);
+ return err;
+ }
+
+ subflow = mptcp_subflow_ctx(sf->sk);
+ subflow->remote_key = msk->remote_key;
+ subflow->local_key = msk->local_key;
+ subflow->token = msk->token;
+
+ sock_hold(sf->sk);
+ release_sock(sk);
+
+ err = kernel_bind(sf, (struct sockaddr *)local,
+ sizeof(struct sockaddr_in));
+ if (err)
+ goto failed;
+
+ mptcp_crypto_key_sha1(subflow->remote_key, &remote_token, NULL);
+ pr_debug("msk=%p remote_token=%u", msk, remote_token);
+ subflow->remote_token = remote_token;
+ subflow->remote_id = remote_id;
+ subflow->request_join = 1;
+ subflow->request_bkup = 1;
+
+ err = kernel_connect(sf, (struct sockaddr *)remote,
+ sizeof(struct sockaddr_in), O_NONBLOCK);
+ if (err && err != -EINPROGRESS)
+ goto failed;
+
+ sock_put(sf->sk);
+ return err;
+
+failed:
+ sock_put(sf->sk);
+ sock_release(sf);
+ return err;
+}
+
int mptcp_subflow_create_socket(struct sock *sk, struct socket **new_sock)
{
struct mptcp_subflow_context *subflow;
--
2.23.0
