From 5a2c3580fc1b0ca53deb62c1b3e0391ce3895dd8 Mon Sep 17 00:00:00 2001 From: cinap_lenrek Date: Sat, 1 Sep 2018 15:08:40 +0200 Subject: [PATCH] ip/dhcpd: bring back interface address for arpenter() the arp table is per interface, so it is possible to have the same netwrok on multiple physical interfaces, tho with different source ip address. one example would be a ethernet and a wlan interface. the mac addresses on these mediums can differ (arp proxying taking place). so provide our source address on the interface we received the request on. the previous change used the ifcaddr; which is correct; but due to a oversight in the kernel, had to match the ip of the arp entry. source address will always work. --- sys/src/cmd/ip/dhcpd/dhcpd.c | 25 +++++++++++++------------ 1 file changed, 13 insertions(+), 12 deletions(-) diff --git a/sys/src/cmd/ip/dhcpd/dhcpd.c b/sys/src/cmd/ip/dhcpd/dhcpd.c index f675bc4d5..f0b24edef 100644 --- a/sys/src/cmd/ip/dhcpd/dhcpd.c +++ b/sys/src/cmd/ip/dhcpd/dhcpd.c @@ -165,7 +165,7 @@ char *optname[256] = void addropt(Req*, int, uchar*); void addrsopt(Req*, int, uchar**, int); -void arpenter(uchar*, uchar*); +void arpenter(uchar*, uchar*, uchar*); void bootp(Req*); void byteopt(Req*, int, uchar); void dhcp(Req*); @@ -746,7 +746,7 @@ sendoffer(Req *rp, uchar *ip, int offer) } else { ipmove(up->raddr, ip); if(bp->htype == 1) - arpenter(up->raddr, bp->chaddr); + arpenter(up->raddr, bp->chaddr, up->laddr); hnputs(up->rport, 68); } @@ -805,7 +805,7 @@ sendack(Req *rp, uchar *ip, int offer, int sendlease) } else { ipmove(up->raddr, ip); if(bp->htype == 1) - arpenter(up->raddr, bp->chaddr); + arpenter(up->raddr, bp->chaddr, up->laddr); hnputs(up->rport, 68); } @@ -993,7 +993,7 @@ bootp(Req *rp) } else { v4tov6(up->raddr, bp->yiaddr); if(bp->htype == 1) - arpenter(up->raddr, bp->chaddr); + arpenter(up->raddr, bp->chaddr, up->laddr); hnputs(up->rport, 68); } @@ -1576,19 +1576,20 @@ hexopt(Req *rp, int t, char *str) } void -arpenter(uchar *ip, uchar *ether) +arpenter(uchar *ip, uchar *mac, uchar *src) { - int f; char buf[256]; + int fd, n; - sprint(buf, "%s/arp", net); - f = open(buf, OWRITE); - if(f < 0){ - syslog(debug, blog, "open %s: %r", buf); + snprint(buf, sizeof buf, "%s/arp", net); + if((fd = open(buf, OWRITE)) < 0){ + warning("couldn't open %s: %r", buf); return; } - fprint(f, "add ether %I %E", ip, ether); - close(f); + n = snprint(buf, sizeof buf, "add ether %I %E %I\n", ip, mac, src); + if(write(fd, buf, n) != n) + warning("arpenter: %s: %r", buf); + close(fd); } char *dhcpmsgname[] =