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| author | David Crawshaw <crawshaw@tailscale.com> | 2021-02-02 10:03:26 -0800 |
|---|---|---|
| committer | David Crawshaw <crawshaw@tailscale.com> | 2021-02-02 10:06:12 -0800 |
| commit | a5166565a7cf201a2d6ac8d207a236db1bce1db3 (patch) | |
| tree | 86d5ade7d218addab0a8e6c06c48b8ed49030abc | |
| parent | 516e8a483807d49b77c775d88fc148db0da8a2cd (diff) | |
| download | tailscale-crawshaw/ipuint.tar.xz tailscale-crawshaw/ipuint.zip | |
net/interfaces: use a uint32_t for ipv4 addresscrawshaw/ipuint
The code was using a C "int", which is a signed 32-bit integer.
That means some valid IP addresses were negative numbers.
(In particular, the default router address handed out by AT&T
fiber: 192.168.1.254. No I don't know why they do that.)
A negative number is < 255, and so was treated by the Go code
as an error.
This fixes the unit test failure:
$ go test -v -run=TestLikelyHomeRouterIPSyscallExec ./net/interfaces
=== RUN TestLikelyHomeRouterIPSyscallExec
interfaces_darwin_cgo_test.go:15: syscall() = invalid IP, false, netstat = 192.168.1.254, true
--- FAIL: TestLikelyHomeRouterIPSyscallExec (0.00s)
Signed-off-by: David Crawshaw <crawshaw@tailscale.com>
| -rw-r--r-- | net/interfaces/interfaces_darwin_cgo.go | 8 |
1 files changed, 4 insertions, 4 deletions
diff --git a/net/interfaces/interfaces_darwin_cgo.go b/net/interfaces/interfaces_darwin_cgo.go index ad9e982c9..df0cd1532 100644 --- a/net/interfaces/interfaces_darwin_cgo.go +++ b/net/interfaces/interfaces_darwin_cgo.go @@ -15,7 +15,7 @@ package interfaces // privateGatewayIPFromRoute returns the private gateway ip address from rtm, if it exists. // Otherwise, it returns 0. -int privateGatewayIPFromRoute(struct rt_msghdr2 *rtm) +uint32_t privateGatewayIPFromRoute(struct rt_msghdr2 *rtm) { // sockaddrs are after the message header struct sockaddr* dst_sa = (struct sockaddr *)(rtm + 1); @@ -38,7 +38,7 @@ int privateGatewayIPFromRoute(struct rt_msghdr2 *rtm) return 0; // gateway not IPv4 struct sockaddr_in* gateway_si= (struct sockaddr_in *)gateway_sa; - int ip; + uint32_t ip; ip = gateway_si->sin_addr.s_addr; unsigned char a, b; @@ -62,7 +62,7 @@ int privateGatewayIPFromRoute(struct rt_msghdr2 *rtm) // If no private gateway IP address was found, it returns 0. // On an error, it returns an error code in (0, 255]. // Any private gateway IP address is > 255. -int privateGatewayIP() +uint32_t privateGatewayIP() { size_t needed; int mib[6]; @@ -90,7 +90,7 @@ int privateGatewayIP() struct rt_msghdr2 *rtm; for (next = buf; next < lim; next += rtm->rtm_msglen) { rtm = (struct rt_msghdr2 *)next; - int ip; + uint32_t ip; ip = privateGatewayIPFromRoute(rtm); if (ip) { free(buf); |