<p>laforge <strong>submitted</strong> this change.</p><p><a href="https://gerrit.osmocom.org/c/osmo-ggsn/+/17801">View Change</a></p><div style="white-space:pre-wrap">Approvals:
laforge: Looks good to me, approved; Verified
</div><pre style="font-family: monospace,monospace; white-space: pre-wrap;">lib/netns.c: Add comments to the code, including doxygen API docs<br><br>Change-Id: I0b20e4870bf62df0a459a621a64a4e2795340ceb<br>---<br>M lib/netns.c<br>1 file changed, 45 insertions(+), 0 deletions(-)<br><br></pre><pre style="font-family: monospace,monospace; white-space: pre-wrap;"><span>diff --git a/lib/netns.c b/lib/netns.c</span><br><span>index 58ae036..1e77a04 100644</span><br><span>--- a/lib/netns.c</span><br><span>+++ b/lib/netns.c</span><br><span>@@ -44,8 +44,13 @@</span><br><span> </span><br><span> #define NETNS_PATH "/var/run/netns"</span><br><span> </span><br><span style="color: hsl(120, 100%, 40%);">+/*! default namespace of the GGSN process */</span><br><span> static int default_nsfd;</span><br><span> </span><br><span style="color: hsl(120, 100%, 40%);">+/*! switch to a (non-default) namespace, store existing signal mask in oldmask.</span><br><span style="color: hsl(120, 100%, 40%);">+ * \param[in] nsfd file descriptor representing the namespace to whch we shall switch</span><br><span style="color: hsl(120, 100%, 40%);">+ * \param[out] oldmask caller-provided memory location to which old signal mask is stored</span><br><span style="color: hsl(120, 100%, 40%);">+ * \ returns 0 on success or negative (errno) in case of error */</span><br><span> int switch_ns(int nsfd, sigset_t *oldmask)</span><br><span> {</span><br><span> sigset_t intmask;</span><br><span>@@ -61,6 +66,9 @@</span><br><span> return 0;</span><br><span> }</span><br><span> </span><br><span style="color: hsl(120, 100%, 40%);">+/*! switch back to the default namespace, restoring signal mask.</span><br><span style="color: hsl(120, 100%, 40%);">+ * \param[in] oldmask signal mask to restore after returning to default namespace</span><br><span style="color: hsl(120, 100%, 40%);">+ * \returns 0 on successs; negative errno value in case of error */</span><br><span> int restore_ns(sigset_t *oldmask)</span><br><span> {</span><br><span> int rc;</span><br><span>@@ -72,25 +80,31 @@</span><br><span> return 0;</span><br><span> }</span><br><span> </span><br><span style="color: hsl(120, 100%, 40%);">+/*! open a file from within specified network namespace */</span><br><span> int open_ns(int nsfd, const char *pathname, int flags)</span><br><span> {</span><br><span> sigset_t intmask, oldmask;</span><br><span> int fd;</span><br><span> int rc;</span><br><span> </span><br><span style="color: hsl(120, 100%, 40%);">+ /* mask off all signals, store old signal mask */</span><br><span> if (sigfillset(&intmask) < 0)</span><br><span> return -errno;</span><br><span> if ((rc = sigprocmask(SIG_BLOCK, &intmask, &oldmask)) != 0)</span><br><span> return -rc;</span><br><span> </span><br><span style="color: hsl(120, 100%, 40%);">+ /* associate the calling thread with namespace file descriptor */</span><br><span> if (setns(nsfd, CLONE_NEWNET) < 0)</span><br><span> return -errno;</span><br><span style="color: hsl(120, 100%, 40%);">+ /* open the requested file/path */</span><br><span> if ((fd = open(pathname, flags)) < 0)</span><br><span> return -errno;</span><br><span style="color: hsl(120, 100%, 40%);">+ /* return back to default namespace */</span><br><span> if (setns(default_nsfd, CLONE_NEWNET) < 0) {</span><br><span> close(fd);</span><br><span> return -errno;</span><br><span> }</span><br><span style="color: hsl(120, 100%, 40%);">+ /* restore process mask */</span><br><span> if ((rc = sigprocmask(SIG_SETMASK, &oldmask, NULL)) != 0) {</span><br><span> close(fd);</span><br><span> return -rc;</span><br><span>@@ -99,26 +113,41 @@</span><br><span> return fd;</span><br><span> }</span><br><span> </span><br><span style="color: hsl(120, 100%, 40%);">+/*! create a socket in another namespace.</span><br><span style="color: hsl(120, 100%, 40%);">+ * Switches temporarily to namespace indicated by nsfd, creates a socket in</span><br><span style="color: hsl(120, 100%, 40%);">+ * that namespace and then returns to the default namespace.</span><br><span style="color: hsl(120, 100%, 40%);">+ * \param[in] nsfd File descriptor of the namspace in which to create socket</span><br><span style="color: hsl(120, 100%, 40%);">+ * \param[in] domain Domain of the socket (AF_INET, ...)</span><br><span style="color: hsl(120, 100%, 40%);">+ * \param[in] type Type of the socket (SOCK_STREAM, ...)</span><br><span style="color: hsl(120, 100%, 40%);">+ * \param[in] protocol Protocol of the socket (IPPROTO_TCP, ...)</span><br><span style="color: hsl(120, 100%, 40%);">+ * \returns 0 on success; negative errno in case of error */</span><br><span> int socket_ns(int nsfd, int domain, int type, int protocol)</span><br><span> {</span><br><span> sigset_t intmask, oldmask;</span><br><span> int sk;</span><br><span> int rc;</span><br><span> </span><br><span style="color: hsl(120, 100%, 40%);">+ /* mask off all signals, store old signal mask */</span><br><span> if (sigfillset(&intmask) < 0)</span><br><span> return -errno;</span><br><span> if ((rc = sigprocmask(SIG_BLOCK, &intmask, &oldmask)) != 0)</span><br><span> return -rc;</span><br><span> </span><br><span style="color: hsl(120, 100%, 40%);">+ /* associate the calling thread with namespace file descriptor */</span><br><span> if (setns(nsfd, CLONE_NEWNET) < 0)</span><br><span> return -errno;</span><br><span style="color: hsl(120, 100%, 40%);">+</span><br><span style="color: hsl(120, 100%, 40%);">+ /* create socket of requested domain/type/proto */</span><br><span> if ((sk = socket(domain, type, protocol)) < 0)</span><br><span> return -errno;</span><br><span style="color: hsl(120, 100%, 40%);">+</span><br><span style="color: hsl(120, 100%, 40%);">+ /* return back to default namespace */</span><br><span> if (setns(default_nsfd, CLONE_NEWNET) < 0) {</span><br><span> close(sk);</span><br><span> return -errno;</span><br><span> }</span><br><span> </span><br><span style="color: hsl(120, 100%, 40%);">+ /* restore process mask */</span><br><span> if ((rc = sigprocmask(SIG_SETMASK, &oldmask, NULL)) != 0) {</span><br><span> close(sk);</span><br><span> return -rc;</span><br><span>@@ -126,13 +155,21 @@</span><br><span> return sk;</span><br><span> }</span><br><span> </span><br><span style="color: hsl(120, 100%, 40%);">+/*! initialize this network namespace helper module.</span><br><span style="color: hsl(120, 100%, 40%);">+ * Must be called before using any other functions of this file.</span><br><span style="color: hsl(120, 100%, 40%);">+ * \returns 0 on success; negative errno in case of error */</span><br><span> int init_netns()</span><br><span> {</span><br><span style="color: hsl(120, 100%, 40%);">+ /* store the default namespace for later reference */</span><br><span> if ((default_nsfd = open("/proc/self/ns/net", O_RDONLY)) < 0)</span><br><span> return -errno;</span><br><span> return 0;</span><br><span> }</span><br><span> </span><br><span style="color: hsl(120, 100%, 40%);">+/*! create obtain file descriptor for network namespace of give name.</span><br><span style="color: hsl(120, 100%, 40%);">+ * Creates /var/run/netns if it doesn't exist already.</span><br><span style="color: hsl(120, 100%, 40%);">+ * \param[in] name Name of the network namespace (in /var/run/netns/)</span><br><span style="color: hsl(120, 100%, 40%);">+ * \returns File descriptor of network namespace; negative errno in case of error */</span><br><span> int get_nsfd(const char *name)</span><br><span> {</span><br><span> int rc;</span><br><span>@@ -140,10 +177,12 @@</span><br><span> sigset_t intmask, oldmask;</span><br><span> char path[MAXPATHLEN] = NETNS_PATH;</span><br><span> </span><br><span style="color: hsl(120, 100%, 40%);">+ /* create /var/run/netns, if it doesn't exist already */</span><br><span> rc = mkdir(path, S_IRWXU|S_IRGRP|S_IXGRP|S_IROTH|S_IXOTH);</span><br><span> if (rc < 0 && errno != EEXIST)</span><br><span> return rc;</span><br><span> </span><br><span style="color: hsl(120, 100%, 40%);">+ /* create /var/run/netns/[name], if it doesn't exist already */</span><br><span> snprintf(path, sizeof(path), "%s/%s", NETNS_PATH, name);</span><br><span> fd = open(path, O_RDONLY|O_CREAT|O_EXCL, 0);</span><br><span> if (fd < 0) {</span><br><span>@@ -157,24 +196,30 @@</span><br><span> if (close(fd) < 0)</span><br><span> return -errno;</span><br><span> </span><br><span style="color: hsl(120, 100%, 40%);">+ /* mask off all signals, store old signal mask */</span><br><span> if (sigfillset(&intmask) < 0)</span><br><span> return -errno;</span><br><span> if ((rc = sigprocmask(SIG_BLOCK, &intmask, &oldmask)) != 0)</span><br><span> return -rc;</span><br><span> </span><br><span style="color: hsl(120, 100%, 40%);">+ /* create a new network namespace */</span><br><span> if (unshare(CLONE_NEWNET) < 0)</span><br><span> return -errno;</span><br><span> if (mount("/proc/self/ns/net", path, "none", MS_BIND, NULL) < 0)</span><br><span> return -errno;</span><br><span> </span><br><span style="color: hsl(120, 100%, 40%);">+ /* switch back to default namespace */</span><br><span> if (setns(default_nsfd, CLONE_NEWNET) < 0)</span><br><span> return -errno;</span><br><span> </span><br><span style="color: hsl(120, 100%, 40%);">+ /* restore process mask */</span><br><span> if ((rc = sigprocmask(SIG_SETMASK, &oldmask, NULL)) != 0)</span><br><span> return -rc;</span><br><span> </span><br><span style="color: hsl(120, 100%, 40%);">+ /* finally, open the created namespace file descriptor from default ns */</span><br><span> if ((fd = open(path, O_RDONLY)) < 0)</span><br><span> return -errno;</span><br><span style="color: hsl(120, 100%, 40%);">+</span><br><span> return fd;</span><br><span> }</span><br><span> </span><br><span></span><br></pre><p>To view, visit <a href="https://gerrit.osmocom.org/c/osmo-ggsn/+/17801">change 17801</a>. 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<div style="display:none"> Gerrit-Project: osmo-ggsn </div>
<div style="display:none"> Gerrit-Branch: master </div>
<div style="display:none"> Gerrit-Change-Id: I0b20e4870bf62df0a459a621a64a4e2795340ceb </div>
<div style="display:none"> Gerrit-Change-Number: 17801 </div>
<div style="display:none"> Gerrit-PatchSet: 3 </div>
<div style="display:none"> Gerrit-Owner: laforge <laforge@osmocom.org> </div>
<div style="display:none"> Gerrit-Reviewer: Jenkins Builder </div>
<div style="display:none"> Gerrit-Reviewer: laforge <laforge@osmocom.org> </div>
<div style="display:none"> Gerrit-Reviewer: pespin <pespin@sysmocom.de> </div>
<div style="display:none"> Gerrit-MessageType: merged </div>