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nl: add separate socket for netlink commands
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avoid re-entrant calls due to netlink events received within
flow/fdb delete loops

Signed-off-by: Felix Fietkau <nbd@nbd.name>
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@nbd168
nbd168 committed May 12, 2023
1 parent d4f56f0 commit 3ea5790
Showing 1 changed file with 66 additions and 29 deletions.
95 changes: 66 additions & 29 deletions nl.c
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Expand Up @@ -15,7 +15,7 @@
#include <linux/tc_act/tc_mirred.h>
#include "bridger.h"

static struct nl_sock *event_sock;
static struct nl_sock *event_sock, *cmd_sock;
static struct uloop_fd event_fd;
static struct uloop_timeout refresh_linkinfo;
static bool ignore_errors;
Expand Down Expand Up @@ -325,6 +325,22 @@ handle_filter(struct nlmsghdr *nh)
flow->idle = idle;
}

static int
bridger_nl_cmd_cb(struct nl_msg *msg, void *arg)
{
struct nlmsghdr *nh = nlmsg_hdr(msg);

switch (nh->nlmsg_type) {
case RTM_NEWTFILTER:
handle_filter(nh);
break;
default:
break;
}

return NL_SKIP;
}

static int
bridger_nl_event_cb(struct nl_msg *msg, void *arg)
{
Expand All @@ -349,9 +365,6 @@ bridger_nl_event_cb(struct nl_msg *msg, void *arg)
case RTM_DELVLAN:
handle_vlan(nh, false);
break;
case RTM_NEWTFILTER:
handle_filter(nh);
break;
default:
break;
}
Expand Down Expand Up @@ -405,10 +418,10 @@ bridger_nl_del_filter(struct device *dev, unsigned int prio)

msg = nlmsg_alloc_simple(RTM_DELTFILTER, NLM_F_REQUEST);
nlmsg_append(msg, &tcmsg, sizeof(tcmsg), NLMSG_ALIGNTO);
nl_send_auto_complete(event_sock, msg);
nl_send_auto_complete(cmd_sock, msg);
nlmsg_free(msg);
ignore_errors = true;
nl_wait_for_ack(event_sock);
nl_wait_for_ack(cmd_sock);
ignore_errors = false;
}

Expand Down Expand Up @@ -451,10 +464,10 @@ bridger_nl_device_prepare(struct device *dev)
msg = nlmsg_alloc_simple(RTM_NEWQDISC, NLM_F_CREATE | NLM_F_EXCL);
nlmsg_append(msg, &tcmsg, sizeof(tcmsg), NLMSG_ALIGNTO);
nla_put_string(msg, TCA_KIND, "clsact");
nl_send_auto_complete(event_sock, msg);
nl_send_auto_complete(cmd_sock, msg);
nlmsg_free(msg);
ignore_errors = true;
nl_wait_for_ack(event_sock);
nl_wait_for_ack(cmd_sock);
ignore_errors = false;
}

Expand Down Expand Up @@ -604,10 +617,10 @@ __bridger_nl_flow_offload_add(struct bridger_flow *flow, struct device *dev)

nla_nest_end(msg, opts);

nl_send_auto_complete(event_sock, msg);
nl_send_auto_complete(cmd_sock, msg);
nlmsg_free(msg);

return nl_wait_for_ack(event_sock);
return nl_wait_for_ack(cmd_sock);
}

int bridger_nl_flow_offload_add(struct bridger_flow *flow)
Expand Down Expand Up @@ -660,9 +673,9 @@ void bridger_nl_flow_offload_update(struct bridger_flow *flow)
dev->offload_update = false;
msg = nlmsg_alloc_simple(RTM_GETTFILTER, NLM_F_REQUEST | NLM_F_DUMP);
nlmsg_append(msg, &tcmsg, sizeof(tcmsg), NLMSG_ALIGNTO);
nl_send_auto_complete(event_sock, msg);
nl_send_auto_complete(cmd_sock, msg);
nlmsg_free(msg);
nl_wait_for_ack(event_sock);
nl_wait_for_ack(cmd_sock);
}

void bridger_nl_flow_offload_del(struct bridger_flow *flow)
Expand All @@ -677,11 +690,11 @@ void bridger_nl_flow_offload_del(struct bridger_flow *flow)
avl_delete(&offload_flows, &flow->offload_node);
flow->offload_ifindex = 0;
msg = bridger_nl_flow_offload_msg(flow, ifindex, RTM_DELTFILTER);
nl_send_auto_complete(event_sock, msg);
nl_send_auto_complete(cmd_sock, msg);
nlmsg_free(msg);

ignore_errors = true;
nl_wait_for_ack(event_sock);
nl_wait_for_ack(cmd_sock);
ignore_errors = false;
}

Expand Down Expand Up @@ -725,12 +738,12 @@ int bridger_nl_fdb_refresh(struct fdb_entry *f)
if (f->key.vlan)
nla_put_u16(msg, NDA_VLAN, f->key.vlan);
nla_put(msg, NDA_LLADDR, ETH_ALEN, f->key.addr);
nl_send_auto_complete(event_sock, msg);
nl_send_auto_complete(cmd_sock, msg);
nlmsg_free(msg);

f->updated = true;

ret = nl_wait_for_ack(event_sock);
ret = nl_wait_for_ack(cmd_sock);
if (ret)
D("Failed to refresh fdb entry %s vid=%d @%s ret=%d\n",
format_macaddr(f->key.addr), f->key.vlan, f->dev->ifname, ret);
Expand Down Expand Up @@ -770,25 +783,57 @@ bridge_nl_error_cb(struct sockaddr_nl *nla, struct nlmsgerr *err,
return NL_STOP;
}

struct nl_sock *
bridger_open_rtnl_socket(void)
{
struct nl_sock *sock;
int opt, fd;

sock = nl_socket_alloc();
if (!sock)
return NULL;

if (nl_connect(sock, NETLINK_ROUTE)) {
nl_socket_free(sock);
return NULL;
}

nl_socket_set_buffer_size(sock, 65536, 0);
nl_cb_err(nl_socket_get_cb(sock), NL_CB_CUSTOM,
bridge_nl_error_cb, NULL);

fd = nl_socket_get_fd(sock);
opt = 1;
setsockopt(fd, SOL_NETLINK, NETLINK_EXT_ACK, &opt, sizeof(opt));

opt = 1;
setsockopt(fd, SOL_NETLINK, NETLINK_CAP_ACK, &opt, sizeof(opt));

return sock;
}


int bridger_nl_init(void)
{
static struct rtgenmsg llmsg = { .rtgen_family = AF_UNSPEC };
static struct ndmsg ndmsg = { .ndm_family = PF_BRIDGE };
static struct br_vlan_msg bvmsg = { .family = PF_BRIDGE };
struct nl_msg *msg;
int opt;

refresh_linkinfo.cb = bridger_refresh_linkinfo_cb;

event_sock = nl_socket_alloc();
if (!event_sock)
cmd_sock = bridger_open_rtnl_socket();
if (!cmd_sock)
return -1;

if (nl_connect(event_sock, NETLINK_ROUTE))
nl_socket_modify_cb(cmd_sock, NL_CB_VALID, NL_CB_CUSTOM,
bridger_nl_cmd_cb, NULL);

event_sock = bridger_open_rtnl_socket();
if (!event_sock)
return -1;

nl_socket_disable_seq_check(event_sock);
nl_socket_set_buffer_size(event_sock, 65536, 0);
nl_socket_modify_cb(event_sock, NL_CB_VALID, NL_CB_CUSTOM,
bridger_nl_event_cb, NULL);
nl_cb_err(nl_socket_get_cb(event_sock), NL_CB_CUSTOM,
Expand All @@ -801,14 +846,6 @@ int bridger_nl_init(void)
event_fd.cb = bridger_nl_sock_cb;
uloop_fd_add(&event_fd, ULOOP_READ);

opt = 1;
setsockopt(event_fd.fd, SOL_NETLINK,
NETLINK_EXT_ACK, &opt, sizeof(opt));

opt = 1;
setsockopt(event_fd.fd, SOL_NETLINK,
NETLINK_CAP_ACK, &opt, sizeof(opt));

nl_send_simple(event_sock, RTM_GETLINK, NLM_F_DUMP | NLM_F_REQUEST, &llmsg, sizeof(llmsg));
nl_wait_for_ack(event_sock);

Expand Down

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