linux/net/ethernet/eth.c

638 lines
17 KiB

[NET] ethernet: Fix first packet goes out with MAC 00:00:00:00:00:00 When you turn off ARP on a netdevice then the first packet always goes out with a dstMAC of all zeroes. This is because the first packet is used to resolve ARP entries. Even though the ARP entry may be resolved (I tried by setting a static ARP entry for a host i was pinging from), it gets overwritten by virtue of having the netdevice disabling ARP. Subsequent packets go out fine with correct dstMAC address (which may be why people have ignored reporting this issue). To cut the story short: the culprit code is in net/ethernet/eth.c::eth_header() ---- /* * Anyway, the loopback-device should never use this function... */ if (dev->flags & (IFF_LOOPBACK|IFF_NOARP)) { memset(eth->h_dest, 0, dev->addr_len); return ETH_HLEN; } if(daddr) { memcpy(eth->h_dest,daddr,dev->addr_len); return ETH_HLEN; } ---- Note how the h_dest is being reset when device has IFF_NOARP. As a note: All devices including loopback pass a daddr. loopback in fact passes a 0 all the time ;-> This means i can delete the check totaly or i can remove the IFF_NOARP Alexey says: -------------------- I think, it was me who did this crap. It was so long ago I do not remember why it was made. I remember some troubles with dummy device. It tried to resolve addresses, apparently, without success and generated errors instead of blackholing. I think the problem was eventually solved at neighbour level. After some thinking I suspect the deletion of this chunk could change behaviour of some parts which do not use neighbour cache f.e. packet socket. I think safer approach would be to move this chunk after if (daddr). And the possibility to remove this completely could be analyzed later. -------------------- Patch updated with Alexey's safer suggestions. Signed-off-by: Jamal Hadi Salim <hadi@cyberus.ca> Acked-by: Alexey Kuznetsov <kuznet@ms2.inr.ac.ru> Signed-off-by: David S. Miller <davem@davemloft.net>
2006-02-23 16:18:01 -08:00
net: add annotations on hh->hh_len lockless accesses KCSAN reported a data-race [1] While we can use READ_ONCE() on the read sides, we need to make sure hh->hh_len is written last. [1] BUG: KCSAN: data-race in eth_header_cache / neigh_resolve_output write to 0xffff8880b9dedcb8 of 4 bytes by task 29760 on cpu 0: eth_header_cache+0xa9/0xd0 net/ethernet/eth.c:247 neigh_hh_init net/core/neighbour.c:1463 [inline] neigh_resolve_output net/core/neighbour.c:1480 [inline] neigh_resolve_output+0x415/0x470 net/core/neighbour.c:1470 neigh_output include/net/neighbour.h:511 [inline] ip6_finish_output2+0x7a2/0xec0 net/ipv6/ip6_output.c:116 __ip6_finish_output net/ipv6/ip6_output.c:142 [inline] __ip6_finish_output+0x2d7/0x330 net/ipv6/ip6_output.c:127 ip6_finish_output+0x41/0x160 net/ipv6/ip6_output.c:152 NF_HOOK_COND include/linux/netfilter.h:294 [inline] ip6_output+0xf2/0x280 net/ipv6/ip6_output.c:175 dst_output include/net/dst.h:436 [inline] NF_HOOK include/linux/netfilter.h:305 [inline] ndisc_send_skb+0x459/0x5f0 net/ipv6/ndisc.c:505 ndisc_send_ns+0x207/0x430 net/ipv6/ndisc.c:647 rt6_probe_deferred+0x98/0xf0 net/ipv6/route.c:615 process_one_work+0x3d4/0x890 kernel/workqueue.c:2269 worker_thread+0xa0/0x800 kernel/workqueue.c:2415 kthread+0x1d4/0x200 drivers/block/aoe/aoecmd.c:1253 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:352 read to 0xffff8880b9dedcb8 of 4 bytes by task 29572 on cpu 1: neigh_resolve_output net/core/neighbour.c:1479 [inline] neigh_resolve_output+0x113/0x470 net/core/neighbour.c:1470 neigh_output include/net/neighbour.h:511 [inline] ip6_finish_output2+0x7a2/0xec0 net/ipv6/ip6_output.c:116 __ip6_finish_output net/ipv6/ip6_output.c:142 [inline] __ip6_finish_output+0x2d7/0x330 net/ipv6/ip6_output.c:127 ip6_finish_output+0x41/0x160 net/ipv6/ip6_output.c:152 NF_HOOK_COND include/linux/netfilter.h:294 [inline] ip6_output+0xf2/0x280 net/ipv6/ip6_output.c:175 dst_output include/net/dst.h:436 [inline] NF_HOOK include/linux/netfilter.h:305 [inline] ndisc_send_skb+0x459/0x5f0 net/ipv6/ndisc.c:505 ndisc_send_ns+0x207/0x430 net/ipv6/ndisc.c:647 rt6_probe_deferred+0x98/0xf0 net/ipv6/route.c:615 process_one_work+0x3d4/0x890 kernel/workqueue.c:2269 worker_thread+0xa0/0x800 kernel/workqueue.c:2415 kthread+0x1d4/0x200 drivers/block/aoe/aoecmd.c:1253 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:352 Reported by Kernel Concurrency Sanitizer on: CPU: 1 PID: 29572 Comm: kworker/1:4 Not tainted 5.4.0-rc6+ #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Workqueue: events rt6_probe_deferred Signed-off-by: Eric Dumazet <edumazet@google.com> Reported-by: syzbot <syzkaller@googlegroups.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2019-11-07 18:29:11 -08:00
of: net: pass the dst buffer to of_get_mac_address() of_get_mac_address() returns a "const void*" pointer to a MAC address. Lately, support to fetch the MAC address by an NVMEM provider was added. But this will only work with platform devices. It will not work with PCI devices (e.g. of an integrated root complex) and esp. not with DSA ports. There is an of_* variant of the nvmem binding which works without devices. The returned data of a nvmem_cell_read() has to be freed after use. On the other hand the return of_get_mac_address() points to some static data without a lifetime. The trick for now, was to allocate a device resource managed buffer which is then returned. This will only work if we have an actual device. Change it, so that the caller of of_get_mac_address() has to supply a buffer where the MAC address is written to. Unfortunately, this will touch all drivers which use the of_get_mac_address(). Usually the code looks like: const char *addr; addr = of_get_mac_address(np); if (!IS_ERR(addr)) ether_addr_copy(ndev->dev_addr, addr); This can then be simply rewritten as: of_get_mac_address(np, ndev->dev_addr); Sometimes is_valid_ether_addr() is used to test the MAC address. of_get_mac_address() already makes sure, it just returns a valid MAC address. Thus we can just test its return code. But we have to be careful if there are still other sources for the MAC address before the of_get_mac_address(). In this case we have to keep the is_valid_ether_addr() call. The following coccinelle patch was used to convert common cases to the new style. Afterwards, I've manually gone over the drivers and fixed the return code variable: either used a new one or if one was already available use that. Mansour Moufid, thanks for that coccinelle patch! <spml> @a@ identifier x; expression y, z; @@ - x = of_get_mac_address(y); + x = of_get_mac_address(y, z); <... - ether_addr_copy(z, x); ...> @@ identifier a.x; @@ - if (<+... x ...+>) {} @@ identifier a.x; @@ if (<+... x ...+>) { ... } - else {} @@ identifier a.x; expression e; @@ - if (<+... x ...+>@e) - {} - else + if (!(e)) {...} @@ expression x, y, z; @@ - x = of_get_mac_address(y, z); + of_get_mac_address(y, z); ... when != x </spml> All drivers, except drivers/net/ethernet/aeroflex/greth.c, were compile-time tested. Suggested-by: Andrew Lunn <andrew@lunn.ch> Signed-off-by: Michael Walle <michael@walle.cc> Reviewed-by: Andrew Lunn <andrew@lunn.ch> Signed-off-by: David S. Miller <davem@davemloft.net>
2021-04-12 19:47:17 +02:00
of: net: pass the dst buffer to of_get_mac_address() of_get_mac_address() returns a "const void*" pointer to a MAC address. Lately, support to fetch the MAC address by an NVMEM provider was added. But this will only work with platform devices. It will not work with PCI devices (e.g. of an integrated root complex) and esp. not with DSA ports. There is an of_* variant of the nvmem binding which works without devices. The returned data of a nvmem_cell_read() has to be freed after use. On the other hand the return of_get_mac_address() points to some static data without a lifetime. The trick for now, was to allocate a device resource managed buffer which is then returned. This will only work if we have an actual device. Change it, so that the caller of of_get_mac_address() has to supply a buffer where the MAC address is written to. Unfortunately, this will touch all drivers which use the of_get_mac_address(). Usually the code looks like: const char *addr; addr = of_get_mac_address(np); if (!IS_ERR(addr)) ether_addr_copy(ndev->dev_addr, addr); This can then be simply rewritten as: of_get_mac_address(np, ndev->dev_addr); Sometimes is_valid_ether_addr() is used to test the MAC address. of_get_mac_address() already makes sure, it just returns a valid MAC address. Thus we can just test its return code. But we have to be careful if there are still other sources for the MAC address before the of_get_mac_address(). In this case we have to keep the is_valid_ether_addr() call. The following coccinelle patch was used to convert common cases to the new style. Afterwards, I've manually gone over the drivers and fixed the return code variable: either used a new one or if one was already available use that. Mansour Moufid, thanks for that coccinelle patch! <spml> @a@ identifier x; expression y, z; @@ - x = of_get_mac_address(y); + x = of_get_mac_address(y, z); <... - ether_addr_copy(z, x); ...> @@ identifier a.x; @@ - if (<+... x ...+>) {} @@ identifier a.x; @@ if (<+... x ...+>) { ... } - else {} @@ identifier a.x; expression e; @@ - if (<+... x ...+>@e) - {} - else + if (!(e)) {...} @@ expression x, y, z; @@ - x = of_get_mac_address(y, z); + of_get_mac_address(y, z); ... when != x </spml> All drivers, except drivers/net/ethernet/aeroflex/greth.c, were compile-time tested. Suggested-by: Andrew Lunn <andrew@lunn.ch> Signed-off-by: Michael Walle <michael@walle.cc> Reviewed-by: Andrew Lunn <andrew@lunn.ch> Signed-off-by: David S. Miller <davem@davemloft.net>
2021-04-12 19:47:17 +02:00
of: net: pass the dst buffer to of_get_mac_address() of_get_mac_address() returns a "const void*" pointer to a MAC address. Lately, support to fetch the MAC address by an NVMEM provider was added. But this will only work with platform devices. It will not work with PCI devices (e.g. of an integrated root complex) and esp. not with DSA ports. There is an of_* variant of the nvmem binding which works without devices. The returned data of a nvmem_cell_read() has to be freed after use. On the other hand the return of_get_mac_address() points to some static data without a lifetime. The trick for now, was to allocate a device resource managed buffer which is then returned. This will only work if we have an actual device. Change it, so that the caller of of_get_mac_address() has to supply a buffer where the MAC address is written to. Unfortunately, this will touch all drivers which use the of_get_mac_address(). Usually the code looks like: const char *addr; addr = of_get_mac_address(np); if (!IS_ERR(addr)) ether_addr_copy(ndev->dev_addr, addr); This can then be simply rewritten as: of_get_mac_address(np, ndev->dev_addr); Sometimes is_valid_ether_addr() is used to test the MAC address. of_get_mac_address() already makes sure, it just returns a valid MAC address. Thus we can just test its return code. But we have to be careful if there are still other sources for the MAC address before the of_get_mac_address(). In this case we have to keep the is_valid_ether_addr() call. The following coccinelle patch was used to convert common cases to the new style. Afterwards, I've manually gone over the drivers and fixed the return code variable: either used a new one or if one was already available use that. Mansour Moufid, thanks for that coccinelle patch! <spml> @a@ identifier x; expression y, z; @@ - x = of_get_mac_address(y); + x = of_get_mac_address(y, z); <... - ether_addr_copy(z, x); ...> @@ identifier a.x; @@ - if (<+... x ...+>) {} @@ identifier a.x; @@ if (<+... x ...+>) { ... } - else {} @@ identifier a.x; expression e; @@ - if (<+... x ...+>@e) - {} - else + if (!(e)) {...} @@ expression x, y, z; @@ - x = of_get_mac_address(y, z); + of_get_mac_address(y, z); ... when != x </spml> All drivers, except drivers/net/ethernet/aeroflex/greth.c, were compile-time tested. Suggested-by: Andrew Lunn <andrew@lunn.ch> Signed-off-by: Michael Walle <michael@walle.cc> Reviewed-by: Andrew Lunn <andrew@lunn.ch> Signed-off-by: David S. Miller <davem@davemloft.net>
2021-04-12 19:47:17 +02:00