在 2024/9/30 15:15, D. Wythe 写道:
On 9/29/24 7:56 PM, Zhu Yanjun wrote:在 2024/9/27 11:42, D. Wythe 写道:From: "D. Wythe" <alibuda@xxxxxxxxxxxxxxxxx> The introduction of IPPROTO_SMC enables eBPF programs to determine whether to use SMC based on the context of socket creation, such as network namespaces, PID and comm name, etc. As a subsequent enhancement, this patch introduces a new hook for eBPF programs that allows decisions on whether to use SMC or not at runtime, including but not limited to local/remote IP address or ports. In simpler words, this feature allows modifications to syn_smc through eBPF programs before the TCP three-way handshake got established. Thanks to kfunc for making it easier for us to implement this feature in SMC. Signed-off-by: D. Wythe <alibuda@xxxxxxxxxxxxxxxxx> --- v1 -> v2: 1. Fix wrong use of ireq->smc_ok, should be rx_opt->smc_ok. 2. Fix compile error when CONFIG_IPV6 or CONFIG_BPF_SYSCALL was not set. --- include/linux/tcp.h | 4 ++- net/ipv4/tcp_input.c | 4 +--net/smc/af_smc.c | 75 +++++++++++++++++++++++++++++++++++++++++ +++++------3 files changed, 72 insertions(+), 11 deletions(-) diff --git a/include/linux/tcp.h b/include/linux/tcp.h index 6a5e08b..d028d76 100644 --- a/include/linux/tcp.h +++ b/include/linux/tcp.h @@ -478,7 +478,9 @@ struct tcp_sock { #endif #if IS_ENABLED(CONFIG_SMC) bool syn_smc; /* SYN includes SMC */ - bool (*smc_hs_congested)(const struct sock *sk); + void (*smc_openreq_init)(struct request_sock *req, + const struct tcp_options_received *rx_opt, + struct sk_buff *skb, const struct sock *sk); #endif #if defined(CONFIG_TCP_MD5SIG) || defined(CONFIG_TCP_AO) diff --git a/net/ipv4/tcp_input.c b/net/ipv4/tcp_input.c index 9f314df..99f34f5 100644 --- a/net/ipv4/tcp_input.c +++ b/net/ipv4/tcp_input.c@@ -7036,8 +7036,8 @@ static void tcp_openreq_init(struct request_sock *req,ireq->ir_num = ntohs(tcp_hdr(skb)->dest); ireq->ir_mark = inet_request_mark(sk, skb); #if IS_ENABLED(CONFIG_SMC) - ireq->smc_ok = rx_opt->smc_ok && !(tcp_sk(sk)->smc_hs_congested && - tcp_sk(sk)->smc_hs_congested(sk)); + if (rx_opt->smc_ok && tcp_sk(sk)->smc_openreq_init) + tcp_sk(sk)->smc_openreq_init(req, rx_opt, skb, sk); #endif } diff --git a/net/smc/af_smc.c b/net/smc/af_smc.c index 0316217..fdac7e2b 100644 --- a/net/smc/af_smc.c +++ b/net/smc/af_smc.c @@ -70,6 +70,15 @@ static void smc_tcp_listen_work(struct work_struct *); static void smc_connect_work(struct work_struct *); +__bpf_hook_start(); ++__weak noinline int select_syn_smc(const struct sock *sk, struct sockaddr *peer)+{ + return 1; +} + +__bpf_hook_end(); +int smc_nl_dump_hs_limitation(struct sk_buff *skb, struct netlink_callback *cb){ struct smc_nl_dmp_ctx *cb_ctx = smc_nl_dmp_ctx(cb);@@ -156,19 +165,43 @@ static struct sock *smc_tcp_syn_recv_sock(const struct sock *sk,return NULL; } -static bool smc_hs_congested(const struct sock *sk) +static void smc_openreq_init(struct request_sock *req, + const struct tcp_options_received *rx_opt, + struct sk_buff *skb, const struct sock *sk) { + struct inet_request_sock *ireq = inet_rsk(req); + struct sockaddr_storage rmt_sockaddr = {0};A trivial problem. The following should be better? struct sockaddr_storage rmt_sockaddr = {};I think, we have discussed this problem in RDMA maillist for several times.Zhu YanjunThis is truly new information to me. Can you provide me with some discussion links?Thanks.
It is a trivial problem. This is the link https://www.spinics.net/lists/linux-rdma/msg119815.html Zhu Yanjun
D. Wytheconst struct smc_sock *smc; smc = smc_clcsock_user_data(sk); if (!smc) - return true; + return; - if (workqueue_congested(WORK_CPU_UNBOUND, smc_hs_wq)) - return true;+ if (smc->limit_smc_hs && workqueue_congested(WORK_CPU_UNBOUND, smc_hs_wq))+ goto out_no_smc; - return false; + rmt_sockaddr.ss_family = sk->sk_family; + + if (rmt_sockaddr.ss_family == AF_INET) {+ struct sockaddr_in *rmt4_sockaddr = (struct sockaddr_in *)&rmt_sockaddr;+ + rmt4_sockaddr->sin_addr.s_addr = ireq->ir_rmt_addr; + rmt4_sockaddr->sin_port = ireq->ir_rmt_port; +#if IS_ENABLED(CONFIG_IPV6) + } else {+ struct sockaddr_in6 *rmt6_sockaddr = (struct sockaddr_in6 *)&rmt_sockaddr;+ + rmt6_sockaddr->sin6_addr = ireq->ir_v6_rmt_addr; + rmt6_sockaddr->sin6_port = ireq->ir_rmt_port; +#endif /* CONFIG_IPV6 */ + } ++ ireq->smc_ok = select_syn_smc(sk, (struct sockaddr *)&rmt_sockaddr);+ return; +out_no_smc: + ireq->smc_ok = 0; + return; } struct smc_hashinfo smc_v4_hashinfo = {@@ -1671,7 +1704,7 @@ int smc_connect(struct socket *sock, struct sockaddr *addr,} smc_copy_sock_settings_to_clc(smc); - tcp_sk(smc->clcsock->sk)->syn_smc = 1; + tcp_sk(smc->clcsock->sk)->syn_smc = select_syn_smc(sk, addr); if (smc->connect_nonblock) { rc = -EALREADY; goto out; @@ -2650,8 +2683,7 @@ int smc_listen(struct socket *sock, int backlog) inet_csk(smc->clcsock->sk)->icsk_af_ops = &smc->af_ops; - if (smc->limit_smc_hs) - tcp_sk(smc->clcsock->sk)->smc_hs_congested = smc_hs_congested; + tcp_sk(smc->clcsock->sk)->smc_openreq_init = smc_openreq_init; rc = kernel_listen(smc->clcsock, backlog); if (rc) {@@ -3475,6 +3507,24 @@ static void __net_exit smc_net_stat_exit(struct net *net).exit = smc_net_stat_exit, }; +#if IS_ENABLED(CONFIG_BPF_SYSCALL) +BTF_SET8_START(bpf_smc_fmodret_ids) +BTF_ID_FLAGS(func, select_syn_smc) +BTF_SET8_END(bpf_smc_fmodret_ids) + +static const struct btf_kfunc_id_set bpf_smc_fmodret_set = { + .owner = THIS_MODULE, + .set = &bpf_smc_fmodret_ids, +}; + +static int bpf_smc_kfunc_init(void) +{ + return register_btf_fmodret_id_set(&bpf_smc_fmodret_set); +} +#else +static inline int bpf_smc_kfunc_init(void) { return 0; } +#endif /* CONFIG_BPF_SYSCALL */ + static int __init smc_init(void) { int rc; @@ -3574,8 +3624,17 @@ static int __init smc_init(void) pr_err("%s: smc_inet_init fails with %d\n", __func__, rc); goto out_ulp; } + + rc = bpf_smc_kfunc_init(); + if (rc) { + pr_err("%s: bpf_smc_kfunc_init fails with %d\n", __func__, rc); + goto out_inet; + } + static_branch_enable(&tcp_have_smc); return 0; +out_inet: + smc_inet_exit(); out_ulp: tcp_unregister_ulp(&smc_ulp_ops); out_lo:
