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Wed, 25 Mar 2026 16:10:41 +0000 (UTC) Received: from dovecot-director2.suse.de ([2a07:de40:b281:106:10:150:64:167]) by imap1.dmz-prg2.suse.org with ESMTPSA id Z6yZNgEJxGnnMwAAD6G6ig (envelope-from ); Wed, 25 Mar 2026 16:10:41 +0000 From: Fernando Fernandez Mancera To: netdev@vger.kernel.org Cc: horms@kernel.org, pabeni@redhat.com, kuba@kernel.org, edumazet@google.com, dsahern@kernel.org, davem@davemloft.net, Fernando Fernandez Mancera Subject: [PATCH 1/2 net-next] ipv4: centralize devconf sysctl handling Date: Wed, 25 Mar 2026 17:10:19 +0100 Message-ID: <20260325161020.3516-1-fmancera@suse.de> X-Mailer: git-send-email 2.51.0 Precedence: bulk X-Mailing-List: netdev@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Spamd-Result: default: False [-3.01 / 50.00]; BAYES_HAM(-3.00)[100.00%]; MID_CONTAINS_FROM(1.00)[]; NEURAL_HAM_LONG(-1.00)[-1.000]; R_MISSING_CHARSET(0.50)[]; R_DKIM_ALLOW(-0.20)[suse.de:s=susede2_rsa,suse.de:s=susede2_ed25519]; NEURAL_HAM_SHORT(-0.20)[-1.000]; MIME_GOOD(-0.10)[text/plain]; MX_GOOD(-0.01)[]; TO_MATCH_ENVRCPT_ALL(0.00)[]; MIME_TRACE(0.00)[0:+]; ARC_NA(0.00)[]; TO_DN_SOME(0.00)[]; DKIM_SIGNED(0.00)[suse.de:s=susede2_rsa,suse.de:s=susede2_ed25519]; RBL_SPAMHAUS_BLOCKED_OPENRESOLVER(0.00)[2a07:de40:b281:104:10:150:64:97:from]; FUZZY_RATELIMITED(0.00)[rspamd.com]; RCVD_TLS_ALL(0.00)[]; DKIM_TRACE(0.00)[suse.de:+]; RCVD_COUNT_TWO(0.00)[2]; FROM_EQ_ENVFROM(0.00)[]; FROM_HAS_DN(0.00)[]; SPAMHAUS_XBL(0.00)[2a07:de40:b281:104:10:150:64:97:from]; DNSWL_BLOCKED(0.00)[2a07:de40:b281:106:10:150:64:167:received,2a07:de40:b281:104:10:150:64:97:from]; RECEIVED_SPAMHAUS_BLOCKED_OPENRESOLVER(0.00)[2a07:de40:b281:106:10:150:64:167:received]; RCPT_COUNT_SEVEN(0.00)[8]; RCVD_VIA_SMTP_AUTH(0.00)[]; DBL_BLOCKED_OPENRESOLVER(0.00)[suse.de:mid,suse.de:dkim,suse.de:email] X-Rspamd-Action: no action X-Spam-Flag: NO X-Spam-Score: -3.01 X-Spam-Level: X-Rspamd-Server: rspamd1.dmz-prg2.suse.org X-Rspamd-Queue-Id: 7F75C4D247 The logic for handling IPv4 devconf sysctls is scattered. Notification and cache flushes are managed in devinet_conf_proc(), while a separate ipv4_doint_and_flush() function and DEVINET_SYSCTL_FLUSHING_ENTRY macro is used for properties that solely require a cache flush. This patch refactors the sysctl handling by introducing a centralized helper, devinet_conf_post_set(). This new function evaluates the changed attribute and handles all necessary operations like triggering netlink notifications. It returns a boolean indicating whether a routing cache flush is required. Note that the boolean is necessary as this function will be re-used for netlink IPv4 devconf handling where the cache flushing must wait until all the attributes have been processed. Finally, this is introducing a small change in behavior for IPV4_DEVCONF_ROUTE_LOCALNET. As commit d0daebc3d622 ("ipv4: Add interface option to enable routing of 127.0.0.0/8") intended, the cache flush should only be performed when ROUTE_LOCALNET changes from 1 to 0. Unfortunately, this was not true because while implementing it the DEVINET_SYSCTL_FLUSHING_ENTRY was used for the attribute, making the code related to it on devinet_conf_proc() dead. IPV4_DEVCONF_FORWARDING is still being handled separately as it requires more operations. Signed-off-by: Fernando Fernandez Mancera --- Note: I ripped of the previous version tag because the patch is now something completely different given the rework of devconf sysctl handling --- net/ipv4/devinet.c | 127 ++++++++++++++++++++++++--------------------- 1 file changed, 68 insertions(+), 59 deletions(-) diff --git a/net/ipv4/devinet.c b/net/ipv4/devinet.c index 58fe7cb69545..c81bb948d59f 100644 --- a/net/ipv4/devinet.c +++ b/net/ipv4/devinet.c @@ -2500,6 +2500,46 @@ static int devinet_conf_ifindex(struct net *net, struct ipv4_devconf *cnf) } } +static bool devinet_conf_post_set(struct net *net, struct ipv4_devconf *cnf, + int attr, int new, int old, int ifindex) +{ + if (new == old) + return false; + + switch (attr) { + case IPV4_DEVCONF_ROUTE_LOCALNET: + case IPV4_DEVCONF_ACCEPT_LOCAL: + if (new == 0) + return true; + break; + case IPV4_DEVCONF_NOXFRM: + case IPV4_DEVCONF_NOPOLICY: + case IPV4_DEVCONF_PROMOTE_SECONDARIES: + case IPV4_DEVCONF_DROP_UNICAST_IN_L2_MULTICAST: + case IPV4_DEVCONF_BC_FORWARDING: + return true; + case IPV4_DEVCONF_RP_FILTER: + inet_netconf_notify_devconf(net, RTM_NEWNETCONF, + NETCONFA_RP_FILTER, + ifindex, cnf); + break; + case IPV4_DEVCONF_PROXY_ARP: + inet_netconf_notify_devconf(net, RTM_NEWNETCONF, + NETCONFA_PROXY_NEIGH, + ifindex, cnf); + break; + case IPV4_DEVCONF_IGNORE_ROUTES_WITH_LINKDOWN: + inet_netconf_notify_devconf(net, RTM_NEWNETCONF, + NETCONFA_IGNORE_ROUTES_WITH_LINKDOWN, + ifindex, cnf); + break; + default: + break; + } + + return false; +} + static int devinet_conf_proc(const struct ctl_table *ctl, int write, void *buffer, size_t *lenp, loff_t *ppos) { @@ -2509,44 +2549,31 @@ static int devinet_conf_proc(const struct ctl_table *ctl, int write, if (write) { struct ipv4_devconf *cnf = ctl->extra1; - struct net *net = ctl->extra2; int i = (int *)ctl->data - cnf->data; + struct net *net = ctl->extra2; int ifindex; - set_bit(i, cnf->state); - - if (cnf == net->ipv4.devconf_dflt) - devinet_copy_dflt_conf(net, i); - if (i == IPV4_DEVCONF_ACCEPT_LOCAL - 1 || - i == IPV4_DEVCONF_ROUTE_LOCALNET - 1) - if ((new_value == 0) && (old_value != 0)) - rt_cache_flush(net); + /* These attributes are bypassing the tracking state, + * for the rest track the state and propagate the changes + * to default config + */ + switch (i + 1) { + case IPV4_DEVCONF_NOXFRM: + case IPV4_DEVCONF_NOPOLICY: + case IPV4_DEVCONF_PROMOTE_SECONDARIES: + case IPV4_DEVCONF_DROP_UNICAST_IN_L2_MULTICAST: + break; + default: + set_bit(i, cnf->state); + if (cnf == net->ipv4.devconf_dflt) + devinet_copy_dflt_conf(net, i); + break; + } - if (i == IPV4_DEVCONF_BC_FORWARDING - 1 && - new_value != old_value) + ifindex = devinet_conf_ifindex(net, cnf); + if (devinet_conf_post_set(net, cnf, i + 1, new_value, + old_value, ifindex)) rt_cache_flush(net); - - if (i == IPV4_DEVCONF_RP_FILTER - 1 && - new_value != old_value) { - ifindex = devinet_conf_ifindex(net, cnf); - inet_netconf_notify_devconf(net, RTM_NEWNETCONF, - NETCONFA_RP_FILTER, - ifindex, cnf); - } - if (i == IPV4_DEVCONF_PROXY_ARP - 1 && - new_value != old_value) { - ifindex = devinet_conf_ifindex(net, cnf); - inet_netconf_notify_devconf(net, RTM_NEWNETCONF, - NETCONFA_PROXY_NEIGH, - ifindex, cnf); - } - if (i == IPV4_DEVCONF_IGNORE_ROUTES_WITH_LINKDOWN - 1 && - new_value != old_value) { - ifindex = devinet_conf_ifindex(net, cnf); - inet_netconf_notify_devconf(net, RTM_NEWNETCONF, - NETCONFA_IGNORE_ROUTES_WITH_LINKDOWN, - ifindex, cnf); - } } return ret; @@ -2599,20 +2626,6 @@ static int devinet_sysctl_forward(const struct ctl_table *ctl, int write, return ret; } -static int ipv4_doint_and_flush(const struct ctl_table *ctl, int write, - void *buffer, size_t *lenp, loff_t *ppos) -{ - int *valp = ctl->data; - int val = *valp; - int ret = proc_dointvec(ctl, write, buffer, lenp, ppos); - struct net *net = ctl->extra2; - - if (write && *valp != val) - rt_cache_flush(net); - - return ret; -} - #define DEVINET_SYSCTL_ENTRY(attr, name, mval, proc) \ { \ .procname = name, \ @@ -2633,9 +2646,6 @@ static int ipv4_doint_and_flush(const struct ctl_table *ctl, int write, #define DEVINET_SYSCTL_COMPLEX_ENTRY(attr, name, proc) \ DEVINET_SYSCTL_ENTRY(attr, name, 0644, proc) -#define DEVINET_SYSCTL_FLUSHING_ENTRY(attr, name) \ - DEVINET_SYSCTL_COMPLEX_ENTRY(attr, name, ipv4_doint_and_flush) - static struct devinet_sysctl_table { struct ctl_table_header *sysctl_header; struct ctl_table devinet_vars[IPV4_DEVCONF_MAX]; @@ -2678,15 +2688,14 @@ static struct devinet_sysctl_table { "ignore_routes_with_linkdown"), DEVINET_SYSCTL_RW_ENTRY(DROP_GRATUITOUS_ARP, "drop_gratuitous_arp"), - - DEVINET_SYSCTL_FLUSHING_ENTRY(NOXFRM, "disable_xfrm"), - DEVINET_SYSCTL_FLUSHING_ENTRY(NOPOLICY, "disable_policy"), - DEVINET_SYSCTL_FLUSHING_ENTRY(PROMOTE_SECONDARIES, - "promote_secondaries"), - DEVINET_SYSCTL_FLUSHING_ENTRY(ROUTE_LOCALNET, - "route_localnet"), - DEVINET_SYSCTL_FLUSHING_ENTRY(DROP_UNICAST_IN_L2_MULTICAST, - "drop_unicast_in_l2_multicast"), + DEVINET_SYSCTL_RW_ENTRY(NOXFRM, "disable_xfrm"), + DEVINET_SYSCTL_RW_ENTRY(NOPOLICY, "disable_policy"), + DEVINET_SYSCTL_RW_ENTRY(PROMOTE_SECONDARIES, + "promote_secondaries"), + DEVINET_SYSCTL_RW_ENTRY(ROUTE_LOCALNET, + "route_localnet"), + DEVINET_SYSCTL_RW_ENTRY(DROP_UNICAST_IN_L2_MULTICAST, + "drop_unicast_in_l2_multicast"), }, }; -- 2.53.0