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loopback: handle EPERM more gracefully

This commit is contained in:
Lennart Poettering 2012-04-13 17:10:21 +02:00
parent a41b539efc
commit 2c3ff76eb0
1 changed files with 58 additions and 15 deletions
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73
src/core/loopback-setup.c
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@ -61,7 +61,8 @@ static ssize_t sendto_loop(int fd, const void *buf, size_t buf_len, int flags, c
for (;;) {
ssize_t l;
if ((l = sendto(fd, buf, buf_len, flags, sa, sa_len)) >= 0)
l = sendto(fd, buf, buf_len, flags, sa, sa_len);
if (l >= 0)
return l;
if (errno != EINTR)
@ -74,7 +75,8 @@ static ssize_t recvfrom_loop(int fd, void *buf, size_t buf_len, int flags, struc
for (;;) {
ssize_t l;
if ((l = recvfrom(fd, buf, buf_len, flags, sa, sa_len)) >= 0)
l = recvfrom(fd, buf, buf_len, flags, sa, sa_len);
if (l >= 0)
return l;
if (errno != EINTR)
@ -112,7 +114,8 @@ static int add_adresses(int fd, int if_loopback, unsigned *requests) {
ifaddrmsg->ifa_scope = RT_SCOPE_HOST;
ifaddrmsg->ifa_index = if_loopback;
if ((r = add_rtattr(&request.header, sizeof(request), IFA_LOCAL, &ipv4_address, sizeof(ipv4_address))) < 0)
r = add_rtattr(&request.header, sizeof(request), IFA_LOCAL, &ipv4_address, sizeof(ipv4_address));
if (r < 0)
return r;
zero(sa);
@ -131,7 +134,8 @@ static int add_adresses(int fd, int if_loopback, unsigned *requests) {
ifaddrmsg->ifa_family = AF_INET6;
ifaddrmsg->ifa_prefixlen = 128;
if ((r = add_rtattr(&request.header, sizeof(request), IFA_LOCAL, &in6addr_loopback, sizeof(in6addr_loopback))) < 0)
r = add_rtattr(&request.header, sizeof(request), IFA_LOCAL, &in6addr_loopback, sizeof(in6addr_loopback));
if (r < 0)
return r;
if (sendto_loop(fd, &request, request.header.nlmsg_len, 0, &sa.sa, sizeof(sa)) < 0)
@ -193,7 +197,8 @@ static int read_response(int fd, unsigned requests_max) {
socklen_t sa_len = sizeof(sa);
struct nlmsgerr *nlmsgerr;
if ((l = recvfrom_loop(fd, &response, sizeof(response), 0, &sa.sa, &sa_len)) < 0)
l = recvfrom_loop(fd, &response, sizeof(response), 0, &sa.sa, &sa_len);
if (l < 0)
return -errno;
if (sa_len != sizeof(sa.nl) ||
@ -217,50 +222,88 @@ static int read_response(int fd, unsigned requests_max) {
nlmsgerr = NLMSG_DATA(&response.header);
if (nlmsgerr->error < 0 && nlmsgerr->error != -EEXIST) {
log_warning("Netlink failure for request %i: %s", response.header.nlmsg_seq, strerror(-nlmsgerr->error));
if (nlmsgerr->error < 0 && nlmsgerr->error != -EEXIST)
return nlmsgerr->error;
}
return response.header.nlmsg_seq;
}
static int check_loopback(void) {
int r, fd;
union {
struct sockaddr sa;
struct sockaddr_in in;
} sa;
/* If we failed to set up the loop back device, check whether
* it might already be set up */
fd = socket(AF_INET, SOCK_DGRAM|SOCK_NONBLOCK|SOCK_CLOEXEC, 0);
if (fd < 0)
return -errno;
zero(sa);
sa.in.sin_family = AF_INET;
sa.in.sin_addr.s_addr = INADDR_LOOPBACK;
if (bind(fd, &sa.sa, sizeof(sa.in)) >= 0)
r = 1;
else
r = errno == EADDRNOTAVAIL ? 0 : -errno;
close_nointr_nofail(fd);
return r;
}
int loopback_setup(void) {
int r, if_loopback;
union {
struct sockaddr sa;
struct sockaddr_nl nl;
struct sockaddr_storage storage;
} sa;
unsigned requests = 0, i;
int fd;
bool eperm = false;
errno = 0;
if ((if_loopback = (int) if_nametoindex("lo")) <= 0)
if_loopback = (int) if_nametoindex("lo");
if (if_loopback <= 0)
return errno ? -errno : -ENODEV;
if ((fd = socket(PF_NETLINK, SOCK_RAW, NETLINK_ROUTE)) < 0)
fd = socket(PF_NETLINK, SOCK_RAW, NETLINK_ROUTE);
if (fd < 0)
return -errno;
zero(sa);
sa.nl.nl_family = AF_NETLINK;
if (bind(fd, &sa.sa, sizeof(sa)) < 0) {
r = -errno;
goto finish;
}
if ((r = add_adresses(fd, if_loopback, &requests)) < 0)
r = add_adresses(fd, if_loopback, &requests);
if (r < 0)
goto finish;
if ((r = start_interface(fd, if_loopback, &requests)) < 0)
r = start_interface(fd, if_loopback, &requests);
if (r < 0)
goto finish;
for (i = 0; i < requests; i++) {
if ((r = read_response(fd, requests)) < 0)
r = read_response(fd, requests);
if (r == -EPERM)
eperm = true;
else if (r < 0)
goto finish;
}
if (eperm && check_loopback() < 0) {
r = -EPERM;
goto finish;
}
r = 0;
finish: