From: David Gibson <david@gibson.dropbear.id.au>
To: Stefano Brivio <sbrivio@redhat.com>, passt-dev@passt.top
Cc: David Gibson <david@gibson.dropbear.id.au>
Subject: [PATCH 08/17] netlink: Treat send() or recv() errors as fatal
Date: Mon, 24 Jul 2023 16:09:27 +1000 [thread overview]
Message-ID: <20230724060936.952659-9-david@gibson.dropbear.id.au> (raw)
In-Reply-To: <20230724060936.952659-1-david@gibson.dropbear.id.au>
Errors on send() or recv() calls on a netlink socket don't indicate errors
with the netlink operations we're attempting, but rather that something's
gone wrong with the mechanics of netlink itself. We don't really expect
this to ever happen, and if it does, it's not clear what we could to to
recover.
So, treat errors from these calls as fatal, rather than returning the error
up the stack. This makes handling failures in the callers of nl_req()
simpler.
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
---
netlink.c | 36 +++++++++++++++++-------------------
1 file changed, 17 insertions(+), 19 deletions(-)
diff --git a/netlink.c b/netlink.c
index 3620fd6..826c926 100644
--- a/netlink.c
+++ b/netlink.c
@@ -103,9 +103,9 @@ fail:
* @req: Request with netlink header
* @len: Request length
*
- * Return: received length on success, negative error code on failure
+ * Return: received length on success, terminates on error
*/
-static int nl_req(int s, char *buf, const void *req, ssize_t len)
+static ssize_t nl_req(int s, char *buf, const void *req, ssize_t len)
{
char flush[NLBUFSIZ];
int done = 0;
@@ -124,11 +124,17 @@ static int nl_req(int s, char *buf, const void *req, ssize_t len)
}
}
- if ((send(s, req, len, 0) < len) ||
- (len = recv(s, buf, NLBUFSIZ, 0)) < 0)
- return -errno;
+ n = send(s, req, len, 0);
+ if (n < 0)
+ die("netlink: Failed to send(): %s", strerror(errno));
+ else if (n < len)
+ die("netlink: Short send");
+
+ n = recv(s, buf, NLBUFSIZ, 0);
+ if (n < 0)
+ die("netlink: Failed to recv(): %s", strerror(errno));
- return len;
+ return n;
}
/**
@@ -158,8 +164,7 @@ unsigned int nl_get_ext_if(int s, sa_family_t af)
ssize_t n;
size_t na;
- if ((n = nl_req(s, buf, &req, sizeof(req))) < 0)
- return 0;
+ n = nl_req(s, buf, &req, sizeof(req));
nh = (struct nlmsghdr *)buf;
@@ -218,8 +223,7 @@ void nl_route_get_def(int s, unsigned int ifi, sa_family_t af, void *gw)
char buf[NLBUFSIZ];
ssize_t n;
- if ((n = nl_req(s, buf, &req, req.nlh.nlmsg_len)) < 0)
- return;
+ n = nl_req(s, buf, &req, req.nlh.nlmsg_len);
for (nh = (struct nlmsghdr *)buf;
NLMSG_OK(nh, n) && nh->nlmsg_type != NLMSG_DONE;
@@ -357,8 +361,7 @@ void nl_route_dup(int s_src, unsigned int ifi_src,
char buf[NLBUFSIZ];
unsigned i;
- if ((nlmsgs_size = nl_req(s_src, buf, &req, req.nlh.nlmsg_len)) < 0)
- return;
+ nlmsgs_size = nl_req(s_src, buf, &req, req.nlh.nlmsg_len);
for (nh = (struct nlmsghdr *)buf, n = nlmsgs_size;
NLMSG_OK(nh, n) && nh->nlmsg_type != NLMSG_DONE;
@@ -434,8 +437,7 @@ void nl_addr_get(int s, unsigned int ifi, sa_family_t af,
char buf[NLBUFSIZ];
ssize_t n;
- if ((n = nl_req(s, buf, &req, req.nlh.nlmsg_len)) < 0)
- return;
+ n = nl_req(s, buf, &req, req.nlh.nlmsg_len);
for (nh = (struct nlmsghdr *)buf;
NLMSG_OK(nh, n) && nh->nlmsg_type != NLMSG_DONE;
@@ -571,8 +573,7 @@ void nl_addr_dup(int s_src, unsigned int ifi_src,
struct nlmsghdr *nh;
ssize_t n;
- if ((n = nl_req(s_src, buf, &req, sizeof(req))) < 0)
- return;
+ n = nl_req(s_src, buf, &req, sizeof(req));
for (nh = (struct nlmsghdr *)buf;
NLMSG_OK(nh, n) && nh->nlmsg_type != NLMSG_DONE;
@@ -632,9 +633,6 @@ void nl_link_get_mac(int s, unsigned int ifi, void *mac)
ssize_t n;
n = nl_req(s, buf, &req, sizeof(req));
- if (n < 0)
- return;
-
for (nh = (struct nlmsghdr *)buf;
NLMSG_OK(nh, n) && nh->nlmsg_type != NLMSG_DONE;
nh = NLMSG_NEXT(nh, n)) {
--
@@ -103,9 +103,9 @@ fail:
* @req: Request with netlink header
* @len: Request length
*
- * Return: received length on success, negative error code on failure
+ * Return: received length on success, terminates on error
*/
-static int nl_req(int s, char *buf, const void *req, ssize_t len)
+static ssize_t nl_req(int s, char *buf, const void *req, ssize_t len)
{
char flush[NLBUFSIZ];
int done = 0;
@@ -124,11 +124,17 @@ static int nl_req(int s, char *buf, const void *req, ssize_t len)
}
}
- if ((send(s, req, len, 0) < len) ||
- (len = recv(s, buf, NLBUFSIZ, 0)) < 0)
- return -errno;
+ n = send(s, req, len, 0);
+ if (n < 0)
+ die("netlink: Failed to send(): %s", strerror(errno));
+ else if (n < len)
+ die("netlink: Short send");
+
+ n = recv(s, buf, NLBUFSIZ, 0);
+ if (n < 0)
+ die("netlink: Failed to recv(): %s", strerror(errno));
- return len;
+ return n;
}
/**
@@ -158,8 +164,7 @@ unsigned int nl_get_ext_if(int s, sa_family_t af)
ssize_t n;
size_t na;
- if ((n = nl_req(s, buf, &req, sizeof(req))) < 0)
- return 0;
+ n = nl_req(s, buf, &req, sizeof(req));
nh = (struct nlmsghdr *)buf;
@@ -218,8 +223,7 @@ void nl_route_get_def(int s, unsigned int ifi, sa_family_t af, void *gw)
char buf[NLBUFSIZ];
ssize_t n;
- if ((n = nl_req(s, buf, &req, req.nlh.nlmsg_len)) < 0)
- return;
+ n = nl_req(s, buf, &req, req.nlh.nlmsg_len);
for (nh = (struct nlmsghdr *)buf;
NLMSG_OK(nh, n) && nh->nlmsg_type != NLMSG_DONE;
@@ -357,8 +361,7 @@ void nl_route_dup(int s_src, unsigned int ifi_src,
char buf[NLBUFSIZ];
unsigned i;
- if ((nlmsgs_size = nl_req(s_src, buf, &req, req.nlh.nlmsg_len)) < 0)
- return;
+ nlmsgs_size = nl_req(s_src, buf, &req, req.nlh.nlmsg_len);
for (nh = (struct nlmsghdr *)buf, n = nlmsgs_size;
NLMSG_OK(nh, n) && nh->nlmsg_type != NLMSG_DONE;
@@ -434,8 +437,7 @@ void nl_addr_get(int s, unsigned int ifi, sa_family_t af,
char buf[NLBUFSIZ];
ssize_t n;
- if ((n = nl_req(s, buf, &req, req.nlh.nlmsg_len)) < 0)
- return;
+ n = nl_req(s, buf, &req, req.nlh.nlmsg_len);
for (nh = (struct nlmsghdr *)buf;
NLMSG_OK(nh, n) && nh->nlmsg_type != NLMSG_DONE;
@@ -571,8 +573,7 @@ void nl_addr_dup(int s_src, unsigned int ifi_src,
struct nlmsghdr *nh;
ssize_t n;
- if ((n = nl_req(s_src, buf, &req, sizeof(req))) < 0)
- return;
+ n = nl_req(s_src, buf, &req, sizeof(req));
for (nh = (struct nlmsghdr *)buf;
NLMSG_OK(nh, n) && nh->nlmsg_type != NLMSG_DONE;
@@ -632,9 +633,6 @@ void nl_link_get_mac(int s, unsigned int ifi, void *mac)
ssize_t n;
n = nl_req(s, buf, &req, sizeof(req));
- if (n < 0)
- return;
-
for (nh = (struct nlmsghdr *)buf;
NLMSG_OK(nh, n) && nh->nlmsg_type != NLMSG_DONE;
nh = NLMSG_NEXT(nh, n)) {
--
2.41.0
next prev parent reply other threads:[~2023-07-24 6:09 UTC|newest]
Thread overview: 35+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-07-24 6:09 [PATCH 00/17] netlink fixes and cleanups David Gibson
2023-07-24 6:09 ` [PATCH 01/17] netlink: Split up functionality if nl_link() David Gibson
2023-08-02 22:47 ` Stefano Brivio
2023-08-03 2:09 ` David Gibson
2023-08-03 4:29 ` David Gibson
2023-08-03 5:39 ` David Gibson
2023-08-03 5:40 ` Stefano Brivio
2023-07-24 6:09 ` [PATCH 02/17] netlink: Split nl_addr() into separate operation functions David Gibson
2023-08-02 22:47 ` Stefano Brivio
2023-08-03 2:11 ` David Gibson
2023-07-24 6:09 ` [PATCH 03/17] netlink: Split nl_route() " David Gibson
2023-08-02 22:47 ` Stefano Brivio
2023-08-03 2:18 ` David Gibson
2023-07-24 6:09 ` [PATCH 04/17] netlink: Use struct in_addr for IPv4 addresses, not bare uint32_t David Gibson
2023-07-24 6:09 ` [PATCH 05/17] netlink: Explicitly pass netlink sockets to operations David Gibson
2023-07-24 6:09 ` [PATCH 06/17] netlink: Make nl_*_dup() use a separate datagram for each request David Gibson
2023-07-24 6:09 ` [PATCH 07/17] netlink: Start sequence number from 1 instead of 0 David Gibson
2023-07-24 6:09 ` David Gibson [this message]
2023-08-02 22:47 ` [PATCH 08/17] netlink: Treat send() or recv() errors as fatal Stefano Brivio
2023-08-03 2:19 ` David Gibson
2023-07-24 6:09 ` [PATCH 09/17] netlink: Fill in netlink header fields from nl_req() David Gibson
2023-07-24 6:09 ` [PATCH 10/17] netlink: Add nl_do() helper for simple operations with error checking David Gibson
2023-08-02 22:48 ` Stefano Brivio
2023-08-03 2:24 ` David Gibson
2023-07-24 6:09 ` [PATCH 11/17] netlink: Clearer reasoning about the netlink response buffer size David Gibson
2023-08-02 22:48 ` Stefano Brivio
2023-08-03 2:22 ` David Gibson
2023-07-24 6:09 ` [PATCH 12/17] netlink: Split nl_req() to allow processing multiple response datagrams David Gibson
2023-07-24 6:09 ` [PATCH 13/17] netlink: Add nl_foreach_oftype to filter response message types David Gibson
2023-07-24 6:09 ` [PATCH 14/17] netlink: Propagate errors for "set" operations David Gibson
2023-07-24 6:09 ` [PATCH 15/17] netlink: Always process all responses to a netlink request David Gibson
2023-07-24 6:09 ` [PATCH 16/17] netlink: Propagate errors for "dump" operations David Gibson
2023-07-24 6:09 ` [PATCH 17/17] netlink: Propagate errors for "dup" operations David Gibson
2023-08-02 22:48 ` Stefano Brivio
2023-08-03 2:26 ` David Gibson
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