From 702c2f646d42cfd9e31133d68a8283fea48fd810 Mon Sep 17 00:00:00 2001 From: Florian Westphal Date: Tue, 3 May 2022 19:38:56 -0700 Subject: [PATCH] mptcp: netlink: allow userspace-driven subflow establishment This allows userspace to tell kernel to add a new subflow to an existing mptcp connection. Userspace provides the token to identify the mptcp-level connection that needs a change in active subflows and the local and remote addresses of the new or the to-be-removed subflow. MPTCP_PM_CMD_SUBFLOW_CREATE requires the following parameters: { token, { loc_id, family, loc_addr4 | loc_addr6 }, { family, rem_addr4 | rem_addr6, rem_port } MPTCP_PM_CMD_SUBFLOW_DESTROY requires the following parameters: { token, { family, loc_addr4 | loc_addr6, loc_port }, { family, rem_addr4 | rem_addr6, rem_port } Acked-by: Paolo Abeni Co-developed-by: Kishen Maloor Signed-off-by: Kishen Maloor Signed-off-by: Florian Westphal Signed-off-by: Mat Martineau Signed-off-by: David S. Miller --- include/uapi/linux/mptcp.h | 3 + net/mptcp/pm_netlink.c | 22 +++++ net/mptcp/pm_userspace.c | 185 +++++++++++++++++++++++++++++++++++++ net/mptcp/protocol.h | 4 + 4 files changed, 214 insertions(+) diff --git a/include/uapi/linux/mptcp.h b/include/uapi/linux/mptcp.h index 11f9fa001a3c..921963589904 100644 --- a/include/uapi/linux/mptcp.h +++ b/include/uapi/linux/mptcp.h @@ -57,6 +57,7 @@ enum { MPTCP_PM_ATTR_SUBFLOWS, /* u32 */ MPTCP_PM_ATTR_TOKEN, /* u32 */ MPTCP_PM_ATTR_LOC_ID, /* u8 */ + MPTCP_PM_ATTR_ADDR_REMOTE, /* nested address */ __MPTCP_PM_ATTR_MAX }; @@ -97,6 +98,8 @@ enum { MPTCP_PM_CMD_SET_FLAGS, MPTCP_PM_CMD_ANNOUNCE, MPTCP_PM_CMD_REMOVE, + MPTCP_PM_CMD_SUBFLOW_CREATE, + MPTCP_PM_CMD_SUBFLOW_DESTROY, __MPTCP_PM_CMD_AFTER_LAST }; diff --git a/net/mptcp/pm_netlink.c b/net/mptcp/pm_netlink.c index a26750f19f65..e099f2a12504 100644 --- a/net/mptcp/pm_netlink.c +++ b/net/mptcp/pm_netlink.c @@ -1096,6 +1096,8 @@ static const struct nla_policy mptcp_pm_policy[MPTCP_PM_ATTR_MAX + 1] = { [MPTCP_PM_ATTR_SUBFLOWS] = { .type = NLA_U32, }, [MPTCP_PM_ATTR_TOKEN] = { .type = NLA_U32, }, [MPTCP_PM_ATTR_LOC_ID] = { .type = NLA_U8, }, + [MPTCP_PM_ATTR_ADDR_REMOTE] = + NLA_POLICY_NESTED(mptcp_pm_addr_policy), }; void mptcp_pm_nl_subflow_chk_stale(const struct mptcp_sock *msk, struct sock *ssk) @@ -1205,6 +1207,16 @@ static int mptcp_pm_parse_pm_addr_attr(struct nlattr *tb[], return err; } +int mptcp_pm_parse_addr(struct nlattr *attr, struct genl_info *info, + struct mptcp_addr_info *addr) +{ + struct nlattr *tb[MPTCP_PM_ADDR_ATTR_MAX + 1]; + + memset(addr, 0, sizeof(*addr)); + + return mptcp_pm_parse_pm_addr_attr(tb, attr, info, addr, true); +} + int mptcp_pm_parse_entry(struct nlattr *attr, struct genl_info *info, bool require_family, struct mptcp_pm_addr_entry *entry) @@ -2210,6 +2222,16 @@ static const struct genl_small_ops mptcp_pm_ops[] = { .doit = mptcp_nl_cmd_remove, .flags = GENL_ADMIN_PERM, }, + { + .cmd = MPTCP_PM_CMD_SUBFLOW_CREATE, + .doit = mptcp_nl_cmd_sf_create, + .flags = GENL_ADMIN_PERM, + }, + { + .cmd = MPTCP_PM_CMD_SUBFLOW_DESTROY, + .doit = mptcp_nl_cmd_sf_destroy, + .flags = GENL_ADMIN_PERM, + }, }; static struct genl_family mptcp_genl_family __ro_after_init = { diff --git a/net/mptcp/pm_userspace.c b/net/mptcp/pm_userspace.c index 3a42c9e66126..f56378e4f597 100644 --- a/net/mptcp/pm_userspace.c +++ b/net/mptcp/pm_userspace.c @@ -242,3 +242,188 @@ int mptcp_nl_cmd_remove(struct sk_buff *skb, struct genl_info *info) sock_put((struct sock *)msk); return err; } + +int mptcp_nl_cmd_sf_create(struct sk_buff *skb, struct genl_info *info) +{ + struct nlattr *raddr = info->attrs[MPTCP_PM_ATTR_ADDR_REMOTE]; + struct nlattr *token = info->attrs[MPTCP_PM_ATTR_TOKEN]; + struct nlattr *laddr = info->attrs[MPTCP_PM_ATTR_ADDR]; + struct mptcp_addr_info addr_r; + struct mptcp_addr_info addr_l; + struct mptcp_sock *msk; + int err = -EINVAL; + struct sock *sk; + u32 token_val; + + if (!laddr || !raddr || !token) { + GENL_SET_ERR_MSG(info, "missing required inputs"); + return err; + } + + token_val = nla_get_u32(token); + + msk = mptcp_token_get_sock(genl_info_net(info), token_val); + if (!msk) { + NL_SET_ERR_MSG_ATTR(info->extack, token, "invalid token"); + return err; + } + + if (!mptcp_pm_is_userspace(msk)) { + GENL_SET_ERR_MSG(info, "invalid request; userspace PM not selected"); + goto create_err; + } + + err = mptcp_pm_parse_addr(laddr, info, &addr_l); + if (err < 0) { + NL_SET_ERR_MSG_ATTR(info->extack, laddr, "error parsing local addr"); + goto create_err; + } + + if (addr_l.id == 0) { + NL_SET_ERR_MSG_ATTR(info->extack, laddr, "missing local addr id"); + goto create_err; + } + + err = mptcp_pm_parse_addr(raddr, info, &addr_r); + if (err < 0) { + NL_SET_ERR_MSG_ATTR(info->extack, raddr, "error parsing remote addr"); + goto create_err; + } + + sk = &msk->sk.icsk_inet.sk; + lock_sock(sk); + + err = __mptcp_subflow_connect(sk, &addr_l, &addr_r); + + release_sock(sk); + + create_err: + sock_put((struct sock *)msk); + return err; +} + +static struct sock *mptcp_nl_find_ssk(struct mptcp_sock *msk, + const struct mptcp_addr_info *local, + const struct mptcp_addr_info *remote) +{ + struct sock *sk = &msk->sk.icsk_inet.sk; + struct mptcp_subflow_context *subflow; + struct sock *found = NULL; + + if (local->family != remote->family) + return NULL; + + lock_sock(sk); + + mptcp_for_each_subflow(msk, subflow) { + const struct inet_sock *issk; + struct sock *ssk; + + ssk = mptcp_subflow_tcp_sock(subflow); + + if (local->family != ssk->sk_family) + continue; + + issk = inet_sk(ssk); + + switch (ssk->sk_family) { + case AF_INET: + if (issk->inet_saddr != local->addr.s_addr || + issk->inet_daddr != remote->addr.s_addr) + continue; + break; +#if IS_ENABLED(CONFIG_MPTCP_IPV6) + case AF_INET6: { + const struct ipv6_pinfo *pinfo = inet6_sk(ssk); + + if (!ipv6_addr_equal(&local->addr6, &pinfo->saddr) || + !ipv6_addr_equal(&remote->addr6, &ssk->sk_v6_daddr)) + continue; + break; + } +#endif + default: + continue; + } + + if (issk->inet_sport == local->port && + issk->inet_dport == remote->port) { + found = ssk; + goto found; + } + } + +found: + release_sock(sk); + + return found; +} + +int mptcp_nl_cmd_sf_destroy(struct sk_buff *skb, struct genl_info *info) +{ + struct nlattr *raddr = info->attrs[MPTCP_PM_ATTR_ADDR_REMOTE]; + struct nlattr *token = info->attrs[MPTCP_PM_ATTR_TOKEN]; + struct nlattr *laddr = info->attrs[MPTCP_PM_ATTR_ADDR]; + struct mptcp_addr_info addr_l; + struct mptcp_addr_info addr_r; + struct mptcp_sock *msk; + struct sock *sk, *ssk; + int err = -EINVAL; + u32 token_val; + + if (!laddr || !raddr || !token) { + GENL_SET_ERR_MSG(info, "missing required inputs"); + return err; + } + + token_val = nla_get_u32(token); + + msk = mptcp_token_get_sock(genl_info_net(info), token_val); + if (!msk) { + NL_SET_ERR_MSG_ATTR(info->extack, token, "invalid token"); + return err; + } + + if (!mptcp_pm_is_userspace(msk)) { + GENL_SET_ERR_MSG(info, "invalid request; userspace PM not selected"); + goto destroy_err; + } + + err = mptcp_pm_parse_addr(laddr, info, &addr_l); + if (err < 0) { + NL_SET_ERR_MSG_ATTR(info->extack, laddr, "error parsing local addr"); + goto destroy_err; + } + + err = mptcp_pm_parse_addr(raddr, info, &addr_r); + if (err < 0) { + NL_SET_ERR_MSG_ATTR(info->extack, raddr, "error parsing remote addr"); + goto destroy_err; + } + + if (addr_l.family != addr_r.family) { + GENL_SET_ERR_MSG(info, "address families do not match"); + goto destroy_err; + } + + if (!addr_l.port || !addr_r.port) { + GENL_SET_ERR_MSG(info, "missing local or remote port"); + goto destroy_err; + } + + sk = &msk->sk.icsk_inet.sk; + ssk = mptcp_nl_find_ssk(msk, &addr_l, &addr_r); + if (ssk) { + struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(ssk); + + mptcp_subflow_shutdown(sk, ssk, RCV_SHUTDOWN | SEND_SHUTDOWN); + mptcp_close_ssk(sk, ssk, subflow); + err = 0; + } else { + err = -ESRCH; + } + + destroy_err: + sock_put((struct sock *)msk); + return err; +} diff --git a/net/mptcp/protocol.h b/net/mptcp/protocol.h index 4026aa3df7f4..f542aeaa5b09 100644 --- a/net/mptcp/protocol.h +++ b/net/mptcp/protocol.h @@ -756,6 +756,8 @@ u16 __mptcp_make_csum(u64 data_seq, u32 subflow_seq, u16 data_len, __wsum sum); void __init mptcp_pm_init(void); void mptcp_pm_data_init(struct mptcp_sock *msk); void mptcp_pm_data_reset(struct mptcp_sock *msk); +int mptcp_pm_parse_addr(struct nlattr *attr, struct genl_info *info, + struct mptcp_addr_info *addr); int mptcp_pm_parse_entry(struct nlattr *attr, struct genl_info *info, bool require_family, struct mptcp_pm_addr_entry *entry); @@ -809,6 +811,8 @@ int mptcp_userspace_pm_append_new_local_addr(struct mptcp_sock *msk, void mptcp_free_local_addr_list(struct mptcp_sock *msk); int mptcp_nl_cmd_announce(struct sk_buff *skb, struct genl_info *info); int mptcp_nl_cmd_remove(struct sk_buff *skb, struct genl_info *info); +int mptcp_nl_cmd_sf_create(struct sk_buff *skb, struct genl_info *info); +int mptcp_nl_cmd_sf_destroy(struct sk_buff *skb, struct genl_info *info); void mptcp_event(enum mptcp_event_type type, const struct mptcp_sock *msk, const struct sock *ssk, gfp_t gfp);