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Fix dropped netlink messages when too many for the buffer #1

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Fix dropped netlink messages when too many for the buffer #1

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27 changes: 22 additions & 5 deletions nlcore.c
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Original file line number Diff line number Diff line change
Expand Up @@ -172,15 +172,26 @@ int nl_send_msg(struct nl_sock *nlsock, char *buf, int len)
int nl_recv_msg(struct nl_sock *nlsock, int type, int (*cb)(struct nlmsghdr *, void *),
void *cb_priv)
{
struct sockaddr_nl sa;
int n;
char buf[4096];
ssize_t n;
char *buf;
struct nlmsghdr *nlhdr;
struct nlmsgerr *errmsg;

while (1) {
n = sizeof(sa);
n = recvfrom(nlsock->sock, buf, sizeof(buf), 0, (struct sockaddr *)&sa, &n);
n = recv(nlsock->sock, NULL, 0, MSG_PEEK|MSG_TRUNC);
if (n < 0) {
if (errno == EINTR || errno == EAGAIN)
continue;
ERRNO("failed to recv");
goto err;
}

DEBUG("prepare to recv %d bytes", n);
buf = malloc(n);
if (!buf)
return -1;

n = recv(nlsock->sock, buf, n, 0);
if (n < 0) {
if (errno == EINTR || errno == EAGAIN)
continue;
Expand All @@ -196,11 +207,13 @@ int nl_recv_msg(struct nl_sock *nlsock, int type, int (*cb)(struct nlmsghdr *, v
if (nlhdr->nlmsg_type == NLMSG_ERROR) {
errmsg = NLMSG_DATA(nlhdr);
DEBUG("err msg: error=%d", errmsg->error);
free(buf);
return -1;
}

if (nlhdr->nlmsg_type == NLMSG_DONE) {
DEBUG("done msg");
free(buf);
return cb(NULL, cb_priv);
}

Expand All @@ -214,12 +227,16 @@ int nl_recv_msg(struct nl_sock *nlsock, int type, int (*cb)(struct nlmsghdr *, v

if (!(nlhdr->nlmsg_flags & NLM_F_MULTI)) {
DEBUG("msg with unset 'multi' flag");
free(buf);
return cb(NULL, cb_priv);
}
}

free(buf);
}

err:
free(buf);
nl_open(nlsock, nlsock->service);
return -1;
}