From e187013abeb4c2a7ec8a4bb978844c7e92a1a6ec Mon Sep 17 00:00:00 2001 From: Akhmat Karakotov Date: Mon, 31 Jan 2022 16:31:21 +0300 Subject: [PATCH] txhash: Make rethinking txhash behavior configurable via sysctl Add a per ns sysctl that controls the txhash rethink behavior: net.core.txrehash. When enabled, the same behavior is retained, when disabled, rethink is not performed. Sysctl is enabled by default. Signed-off-by: Akhmat Karakotov Reviewed-by: Eric Dumazet Signed-off-by: David S. Miller --- include/net/netns/core.h | 1 + include/net/sock.h | 34 +++++++++++++++++++++------------- include/uapi/linux/socket.h | 3 +++ net/core/net_namespace.c | 2 ++ net/core/sysctl_net_core.c | 14 ++++++++++++-- 5 files changed, 39 insertions(+), 15 deletions(-) diff --git a/include/net/netns/core.h b/include/net/netns/core.h index 552bc25..388244e 100644 --- a/include/net/netns/core.h +++ b/include/net/netns/core.h @@ -10,6 +10,7 @@ struct netns_core { struct ctl_table_header *sysctl_hdr; int sysctl_somaxconn; + u8 sysctl_txrehash; #ifdef CONFIG_PROC_FS struct prot_inuse __percpu *prot_inuse; diff --git a/include/net/sock.h b/include/net/sock.h index ff9b508..0540e1b 100644 --- a/include/net/sock.h +++ b/include/net/sock.h @@ -587,6 +587,18 @@ static inline bool sk_user_data_is_nocopy(const struct sock *sk) __tmp | SK_USER_DATA_NOCOPY); \ }) +static inline +struct net *sock_net(const struct sock *sk) +{ + return read_pnet(&sk->sk_net); +} + +static inline +void sock_net_set(struct sock *sk, struct net *net) +{ + write_pnet(&sk->sk_net, net); +} + /* * SK_CAN_REUSE and SK_NO_REUSE on a socket mean that the socket is OK * or not whether his port will be reused by someone else. SK_FORCE_REUSE @@ -2054,10 +2066,18 @@ static inline void sk_set_txhash(struct sock *sk) static inline bool sk_rethink_txhash(struct sock *sk) { - if (sk->sk_txhash) { + u8 rehash; + + if (!sk->sk_txhash) + return false; + + rehash = READ_ONCE(sock_net(sk)->core.sysctl_txrehash); + + if (rehash) { sk_set_txhash(sk); return true; } + return false; } @@ -2704,18 +2724,6 @@ static inline void sk_eat_skb(struct sock *sk, struct sk_buff *skb) __kfree_skb(skb); } -static inline -struct net *sock_net(const struct sock *sk) -{ - return read_pnet(&sk->sk_net); -} - -static inline -void sock_net_set(struct sock *sk, struct net *net) -{ - write_pnet(&sk->sk_net, net); -} - static inline bool skb_sk_is_prefetched(struct sk_buff *skb) { diff --git a/include/uapi/linux/socket.h b/include/uapi/linux/socket.h index eb0a9a5..0accd61 100644 --- a/include/uapi/linux/socket.h +++ b/include/uapi/linux/socket.h @@ -31,4 +31,7 @@ struct __kernel_sockaddr_storage { #define SOCK_BUF_LOCK_MASK (SOCK_SNDBUF_LOCK | SOCK_RCVBUF_LOCK) +#define SOCK_TXREHASH_DISABLED 0 +#define SOCK_TXREHASH_ENABLED 1 + #endif /* _UAPI_LINUX_SOCKET_H */ diff --git a/net/core/net_namespace.c b/net/core/net_namespace.c index c53d9aa..8711350 100644 --- a/net/core/net_namespace.c +++ b/net/core/net_namespace.c @@ -364,6 +364,8 @@ out_undo: static int __net_init net_defaults_init_net(struct net *net) { net->core.sysctl_somaxconn = SOMAXCONN; + net->core.sysctl_txrehash = SOCK_TXREHASH_ENABLED; + return 0; } diff --git a/net/core/sysctl_net_core.c b/net/core/sysctl_net_core.c index 7b4d485..dbeb8ec 100644 --- a/net/core/sysctl_net_core.c +++ b/net/core/sysctl_net_core.c @@ -593,6 +593,15 @@ static struct ctl_table netns_core_table[] = { .extra1 = SYSCTL_ZERO, .proc_handler = proc_dointvec_minmax }, + { + .procname = "txrehash", + .data = &init_net.core.sysctl_txrehash, + .maxlen = sizeof(u8), + .mode = 0644, + .extra1 = SYSCTL_ZERO, + .extra2 = SYSCTL_ONE, + .proc_handler = proc_dou8vec_minmax, + }, { } }; @@ -611,7 +620,7 @@ __setup("fb_tunnels=", fb_tunnels_only_for_init_net_sysctl_setup); static __net_init int sysctl_core_net_init(struct net *net) { - struct ctl_table *tbl; + struct ctl_table *tbl, *tmp; tbl = netns_core_table; if (!net_eq(net, &init_net)) { @@ -619,7 +628,8 @@ static __net_init int sysctl_core_net_init(struct net *net) if (tbl == NULL) goto err_dup; - tbl[0].data = &net->core.sysctl_somaxconn; + for (tmp = tbl; tmp->procname; tmp++) + tmp->data += (char *)net - (char *)&init_net; /* Don't export any sysctls to unprivileged users */ if (net->user_ns != &init_user_ns) { -- 2.7.4