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 Yanjun
This is truly new information to me. Can you provide me with some discussion links? Thanks. D. Wythe
const 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:
