Skip to content

L
linux
Commit 374edea4 authored by David S. Miller's avatar David S. Miller
Browse files
Options

Merge branch 'ip6_gre-Fixes-in-headroom-handling' 

Petr Machata says:

====================
net: ip6_gre: Fixes in headroom handling

This series mends some problems in headroom management in ip6_gre
module. The current code base has the following three closely-related
problems:

- ip6gretap tunnels neglect to ensure there's enough writable headroom
  before pushing GRE headers.

- ip6erspan does this, but assumes that dev->needed_headroom is primed.
  But that doesn't happen until ip6_tnl_xmit() is called later. Thus for
  the first packet, ip6erspan actually behaves like ip6gretap above.

- ip6erspan shares some of the code with ip6gretap, including
  calculations of needed header length. While there is custom
  ERSPAN-specific code for calculating the headroom, the computed
  values are overwritten by the ip6gretap code.

The first two issues lead to a kernel panic in situations where a packet
is mirrored from a veth device to the device in question. They are
fixed, respectively, in patches #1 and #2, which include the full panic
trace and a reproducer.

The rest of the patchset deals with the last issue. In patches #3 to #6,
several functions are split up into reusable parts. Finally in patch #7
these blocks are used to compose ERSPAN-specific callbacks where
necessary to fix the hlen calculation.
====================
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parents 02f99df1 2d665034
Hide whitespace changes
Inline Side-by-side
Showing with 145 additions and 39 deletions
net/ipv6/ip6_gre.c
View file @ 374edea4
...@@ -81,6 +81,7 @@ static int ip6gre_tunnel_init(struct net_device *dev); ...@@ -81,6 +81,7 @@ static int ip6gre_tunnel_init(struct net_device *dev);
static void ip6gre_tunnel_setup(struct net_device *dev); static void ip6gre_tunnel_setup(struct net_device *dev);
static void ip6gre_tunnel_link(struct ip6gre_net *ign, struct ip6_tnl *t); static void ip6gre_tunnel_link(struct ip6gre_net *ign, struct ip6_tnl *t);
static void ip6gre_tnl_link_config(struct ip6_tnl *t, int set_mtu); static void ip6gre_tnl_link_config(struct ip6_tnl *t, int set_mtu);
static void ip6erspan_tnl_link_config(struct ip6_tnl *t, int set_mtu);
/* Tunnel hash table */ /* Tunnel hash table */
...@@ -698,6 +699,9 @@ static netdev_tx_t __gre6_xmit(struct sk_buff *skb, ...@@ -698,6 +699,9 @@ static netdev_tx_t __gre6_xmit(struct sk_buff *skb,
else else
fl6->daddr = tunnel->parms.raddr; fl6->daddr = tunnel->parms.raddr;
if (skb_cow_head(skb, dev->needed_headroom ?: tunnel->hlen))
return -ENOMEM;
/* Push GRE header. */ /* Push GRE header. */
protocol = (dev->type == ARPHRD_ETHER) ? htons(ETH_P_TEB) : proto; protocol = (dev->type == ARPHRD_ETHER) ? htons(ETH_P_TEB) : proto;
...@@ -908,7 +912,7 @@ static netdev_tx_t ip6erspan_tunnel_xmit(struct sk_buff *skb, ...@@ -908,7 +912,7 @@ static netdev_tx_t ip6erspan_tunnel_xmit(struct sk_buff *skb,
truncate = true; truncate = true;
} }
if (skb_cow_head(skb, dev->needed_headroom)) if (skb_cow_head(skb, dev->needed_headroom ?: t->hlen))
goto tx_err; goto tx_err;
t->parms.o_flags &= ~TUNNEL_KEY; t->parms.o_flags &= ~TUNNEL_KEY;
...@@ -1022,12 +1026,11 @@ static netdev_tx_t ip6erspan_tunnel_xmit(struct sk_buff *skb, ...@@ -1022,12 +1026,11 @@ static netdev_tx_t ip6erspan_tunnel_xmit(struct sk_buff *skb,
return NETDEV_TX_OK; return NETDEV_TX_OK;
} }
static void ip6gre_tnl_link_config(struct ip6_tnl *t, int set_mtu) static void ip6gre_tnl_link_config_common(struct ip6_tnl *t)
{ {
struct net_device *dev = t->dev; struct net_device *dev = t->dev;
struct __ip6_tnl_parm *p = &t->parms; struct __ip6_tnl_parm *p = &t->parms;
struct flowi6 *fl6 = &t->fl.u.ip6; struct flowi6 *fl6 = &t->fl.u.ip6;
int t_hlen;
if (dev->type != ARPHRD_ETHER) { if (dev->type != ARPHRD_ETHER) {
memcpy(dev->dev_addr, &p->laddr, sizeof(struct in6_addr)); memcpy(dev->dev_addr, &p->laddr, sizeof(struct in6_addr));
...@@ -1054,12 +1057,13 @@ static void ip6gre_tnl_link_config(struct ip6_tnl *t, int set_mtu) ...@@ -1054,12 +1057,13 @@ static void ip6gre_tnl_link_config(struct ip6_tnl *t, int set_mtu)
dev->flags |= IFF_POINTOPOINT; dev->flags |= IFF_POINTOPOINT;
else else
dev->flags &= ~IFF_POINTOPOINT; dev->flags &= ~IFF_POINTOPOINT;
}
t->tun_hlen = gre_calc_hlen(t->parms.o_flags); static void ip6gre_tnl_link_config_route(struct ip6_tnl *t, int set_mtu,
int t_hlen)
t->hlen = t->encap_hlen + t->tun_hlen; {
const struct __ip6_tnl_parm *p = &t->parms;
t_hlen = t->hlen + sizeof(struct ipv6hdr); struct net_device *dev = t->dev;
if (p->flags & IP6_TNL_F_CAP_XMIT) { if (p->flags & IP6_TNL_F_CAP_XMIT) {
int strict = (ipv6_addr_type(&p->raddr) & int strict = (ipv6_addr_type(&p->raddr) &
...@@ -1091,8 +1095,26 @@ static void ip6gre_tnl_link_config(struct ip6_tnl *t, int set_mtu) ...@@ -1091,8 +1095,26 @@ static void ip6gre_tnl_link_config(struct ip6_tnl *t, int set_mtu)
} }
} }
static int ip6gre_tnl_change(struct ip6_tnl *t, static int ip6gre_calc_hlen(struct ip6_tnl *tunnel)
const struct __ip6_tnl_parm *p, int set_mtu) {
int t_hlen;
tunnel->tun_hlen = gre_calc_hlen(tunnel->parms.o_flags);
tunnel->hlen = tunnel->tun_hlen + tunnel->encap_hlen;
t_hlen = tunnel->hlen + sizeof(struct ipv6hdr);
tunnel->dev->hard_header_len = LL_MAX_HEADER + t_hlen;
return t_hlen;
}
static void ip6gre_tnl_link_config(struct ip6_tnl *t, int set_mtu)
{
ip6gre_tnl_link_config_common(t);
ip6gre_tnl_link_config_route(t, set_mtu, ip6gre_calc_hlen(t));
}
static void ip6gre_tnl_copy_tnl_parm(struct ip6_tnl *t,
const struct __ip6_tnl_parm *p)
{ {
t->parms.laddr = p->laddr; t->parms.laddr = p->laddr;
t->parms.raddr = p->raddr; t->parms.raddr = p->raddr;
...@@ -1108,6 +1130,12 @@ static int ip6gre_tnl_change(struct ip6_tnl *t, ...@@ -1108,6 +1130,12 @@ static int ip6gre_tnl_change(struct ip6_tnl *t,
t->parms.o_flags = p->o_flags; t->parms.o_flags = p->o_flags;
t->parms.fwmark = p->fwmark; t->parms.fwmark = p->fwmark;
dst_cache_reset(&t->dst_cache); dst_cache_reset(&t->dst_cache);
}
static int ip6gre_tnl_change(struct ip6_tnl *t, const struct __ip6_tnl_parm *p,
int set_mtu)
{
ip6gre_tnl_copy_tnl_parm(t, p);
ip6gre_tnl_link_config(t, set_mtu); ip6gre_tnl_link_config(t, set_mtu);
return 0; return 0;
} }
...@@ -1384,11 +1412,7 @@ static int ip6gre_tunnel_init_common(struct net_device *dev) ...@@ -1384,11 +1412,7 @@ static int ip6gre_tunnel_init_common(struct net_device *dev)
return ret; return ret;
} }
tunnel->tun_hlen = gre_calc_hlen(tunnel->parms.o_flags); t_hlen = ip6gre_calc_hlen(tunnel);
tunnel->hlen = tunnel->tun_hlen + tunnel->encap_hlen;
t_hlen = tunnel->hlen + sizeof(struct ipv6hdr);
dev->hard_header_len = LL_MAX_HEADER + t_hlen;
dev->mtu = ETH_DATA_LEN - t_hlen; dev->mtu = ETH_DATA_LEN - t_hlen;
if (dev->type == ARPHRD_ETHER) if (dev->type == ARPHRD_ETHER)
dev->mtu -= ETH_HLEN; dev->mtu -= ETH_HLEN;
...@@ -1731,6 +1755,19 @@ static const struct net_device_ops ip6gre_tap_netdev_ops = { ...@@ -1731,6 +1755,19 @@ static const struct net_device_ops ip6gre_tap_netdev_ops = {
.ndo_get_iflink = ip6_tnl_get_iflink, .ndo_get_iflink = ip6_tnl_get_iflink,
}; };
static int ip6erspan_calc_hlen(struct ip6_tnl *tunnel)
{
int t_hlen;
tunnel->tun_hlen = 8;
tunnel->hlen = tunnel->tun_hlen + tunnel->encap_hlen +
erspan_hdr_len(tunnel->parms.erspan_ver);
t_hlen = tunnel->hlen + sizeof(struct ipv6hdr);
tunnel->dev->hard_header_len = LL_MAX_HEADER + t_hlen;
return t_hlen;
}
static int ip6erspan_tap_init(struct net_device *dev) static int ip6erspan_tap_init(struct net_device *dev)
{ {
struct ip6_tnl *tunnel; struct ip6_tnl *tunnel;
...@@ -1754,12 +1791,7 @@ static int ip6erspan_tap_init(struct net_device *dev) ...@@ -1754,12 +1791,7 @@ static int ip6erspan_tap_init(struct net_device *dev)
return ret; return ret;
} }
tunnel->tun_hlen = 8; t_hlen = ip6erspan_calc_hlen(tunnel);
tunnel->hlen = tunnel->tun_hlen + tunnel->encap_hlen +
erspan_hdr_len(tunnel->parms.erspan_ver);
t_hlen = tunnel->hlen + sizeof(struct ipv6hdr);
dev->hard_header_len = LL_MAX_HEADER + t_hlen;
dev->mtu = ETH_DATA_LEN - t_hlen; dev->mtu = ETH_DATA_LEN - t_hlen;
if (dev->type == ARPHRD_ETHER) if (dev->type == ARPHRD_ETHER)
dev->mtu -= ETH_HLEN; dev->mtu -= ETH_HLEN;
...@@ -1767,7 +1799,7 @@ static int ip6erspan_tap_init(struct net_device *dev) ...@@ -1767,7 +1799,7 @@ static int ip6erspan_tap_init(struct net_device *dev)
dev->mtu -= 8; dev->mtu -= 8;
dev->priv_flags |= IFF_LIVE_ADDR_CHANGE; dev->priv_flags |= IFF_LIVE_ADDR_CHANGE;
ip6gre_tnl_link_config(tunnel, 1); ip6erspan_tnl_link_config(tunnel, 1);
return 0; return 0;
} }
...@@ -1838,9 +1870,9 @@ static bool ip6gre_netlink_encap_parms(struct nlattr *data[], ...@@ -1838,9 +1870,9 @@ static bool ip6gre_netlink_encap_parms(struct nlattr *data[],
return ret; return ret;
} }
static int ip6gre_newlink(struct net *src_net, struct net_device *dev, static int ip6gre_newlink_common(struct net *src_net, struct net_device *dev,
struct nlattr *tb[], struct nlattr *data[], struct nlattr *tb[], struct nlattr *data[],
struct netlink_ext_ack *extack) struct netlink_ext_ack *extack)
{ {
struct ip6_tnl *nt; struct ip6_tnl *nt;
struct net *net = dev_net(dev); struct net *net = dev_net(dev);
...@@ -1877,49 +1909,76 @@ static int ip6gre_newlink(struct net *src_net, struct net_device *dev, ...@@ -1877,49 +1909,76 @@ static int ip6gre_newlink(struct net *src_net, struct net_device *dev,
if (err) if (err)
goto out; goto out;
ip6gre_tnl_link_config(nt, !tb[IFLA_MTU]);
if (tb[IFLA_MTU]) if (tb[IFLA_MTU])
ip6_tnl_change_mtu(dev, nla_get_u32(tb[IFLA_MTU])); ip6_tnl_change_mtu(dev, nla_get_u32(tb[IFLA_MTU]));
dev_hold(dev); dev_hold(dev);
ip6gre_tunnel_link(ign, nt);
out: out:
return err; return err;
} }
static int ip6gre_changelink(struct net_device *dev, struct nlattr *tb[], static int ip6gre_newlink(struct net *src_net, struct net_device *dev,
struct nlattr *data[], struct nlattr *tb[], struct nlattr *data[],
struct netlink_ext_ack *extack) struct netlink_ext_ack *extack)
{
int err = ip6gre_newlink_common(src_net, dev, tb, data, extack);
struct ip6_tnl *nt = netdev_priv(dev);
struct net *net = dev_net(dev);
if (!err) {
ip6gre_tnl_link_config(nt, !tb[IFLA_MTU]);
ip6gre_tunnel_link(net_generic(net, ip6gre_net_id), nt);
}
return err;
}
static struct ip6_tnl *
ip6gre_changelink_common(struct net_device *dev, struct nlattr *tb[],
struct nlattr *data[], struct __ip6_tnl_parm *p_p,
struct netlink_ext_ack *extack)
{ {
struct ip6_tnl *t, *nt = netdev_priv(dev); struct ip6_tnl *t, *nt = netdev_priv(dev);
struct net *net = nt->net; struct net *net = nt->net;
struct ip6gre_net *ign = net_generic(net, ip6gre_net_id); struct ip6gre_net *ign = net_generic(net, ip6gre_net_id);
struct __ip6_tnl_parm p;
struct ip_tunnel_encap ipencap; struct ip_tunnel_encap ipencap;
if (dev == ign->fb_tunnel_dev) if (dev == ign->fb_tunnel_dev)
return -EINVAL; return ERR_PTR(-EINVAL);
if (ip6gre_netlink_encap_parms(data, &ipencap)) { if (ip6gre_netlink_encap_parms(data, &ipencap)) {
int err = ip6_tnl_encap_setup(nt, &ipencap); int err = ip6_tnl_encap_setup(nt, &ipencap);
if (err < 0) if (err < 0)
return err; return ERR_PTR(err);
} }
ip6gre_netlink_parms(data, &p); ip6gre_netlink_parms(data, p_p);
t = ip6gre_tunnel_locate(net, &p, 0); t = ip6gre_tunnel_locate(net, p_p, 0);
if (t) { if (t) {
if (t->dev != dev) if (t->dev != dev)
return -EEXIST; return ERR_PTR(-EEXIST);
} else { } else {
t = nt; t = nt;
} }
return t;
}
static int ip6gre_changelink(struct net_device *dev, struct nlattr *tb[],
struct nlattr *data[],
struct netlink_ext_ack *extack)
{
struct ip6gre_net *ign = net_generic(dev_net(dev), ip6gre_net_id);
struct __ip6_tnl_parm p;
struct ip6_tnl *t;
t = ip6gre_changelink_common(dev, tb, data, &p, extack);
if (IS_ERR(t))
return PTR_ERR(t);
ip6gre_tunnel_unlink(ign, t); ip6gre_tunnel_unlink(ign, t);
ip6gre_tnl_change(t, &p, !tb[IFLA_MTU]); ip6gre_tnl_change(t, &p, !tb[IFLA_MTU]);
ip6gre_tunnel_link(ign, t); ip6gre_tunnel_link(ign, t);
...@@ -2071,6 +2130,53 @@ static void ip6erspan_tap_setup(struct net_device *dev) ...@@ -2071,6 +2130,53 @@ static void ip6erspan_tap_setup(struct net_device *dev)
netif_keep_dst(dev); netif_keep_dst(dev);
} }
static int ip6erspan_newlink(struct net *src_net, struct net_device *dev,
struct nlattr *tb[], struct nlattr *data[],
struct netlink_ext_ack *extack)
{
int err = ip6gre_newlink_common(src_net, dev, tb, data, extack);
struct ip6_tnl *nt = netdev_priv(dev);
struct net *net = dev_net(dev);
if (!err) {
ip6erspan_tnl_link_config(nt, !tb[IFLA_MTU]);
ip6gre_tunnel_link(net_generic(net, ip6gre_net_id), nt);
}
return err;
}
static void ip6erspan_tnl_link_config(struct ip6_tnl *t, int set_mtu)
{
ip6gre_tnl_link_config_common(t);
ip6gre_tnl_link_config_route(t, set_mtu, ip6erspan_calc_hlen(t));
}
static int ip6erspan_tnl_change(struct ip6_tnl *t,
const struct __ip6_tnl_parm *p, int set_mtu)
{
ip6gre_tnl_copy_tnl_parm(t, p);
ip6erspan_tnl_link_config(t, set_mtu);
return 0;
}
static int ip6erspan_changelink(struct net_device *dev, struct nlattr *tb[],
struct nlattr *data[],
struct netlink_ext_ack *extack)
{
struct ip6gre_net *ign = net_generic(dev_net(dev), ip6gre_net_id);
struct __ip6_tnl_parm p;
struct ip6_tnl *t;
t = ip6gre_changelink_common(dev, tb, data, &p, extack);
if (IS_ERR(t))
return PTR_ERR(t);
ip6gre_tunnel_unlink(ign, t);
ip6erspan_tnl_change(t, &p, !tb[IFLA_MTU]);
ip6gre_tunnel_link(ign, t);
return 0;
}
static struct rtnl_link_ops ip6gre_link_ops __read_mostly = { static struct rtnl_link_ops ip6gre_link_ops __read_mostly = {
.kind = "ip6gre", .kind = "ip6gre",
.maxtype = IFLA_GRE_MAX, .maxtype = IFLA_GRE_MAX,
...@@ -2107,8 +2213,8 @@ static struct rtnl_link_ops ip6erspan_tap_ops __read_mostly = { ...@@ -2107,8 +2213,8 @@ static struct rtnl_link_ops ip6erspan_tap_ops __read_mostly = {
.priv_size = sizeof(struct ip6_tnl), .priv_size = sizeof(struct ip6_tnl),
.setup = ip6erspan_tap_setup, .setup = ip6erspan_tap_setup,
.validate = ip6erspan_tap_validate, .validate = ip6erspan_tap_validate,
.newlink = ip6gre_newlink, .newlink = ip6erspan_newlink,
.changelink = ip6gre_changelink, .changelink = ip6erspan_changelink,
.get_size = ip6gre_get_size, .get_size = ip6gre_get_size,
.fill_info = ip6gre_fill_info, .fill_info = ip6gre_fill_info,
.get_link_net = ip6_tnl_get_link_net, .get_link_net = ip6_tnl_get_link_net,
......
Markdown is supported
0% or
You are about to add 0 people to the discussion. Proceed with caution.
Finish editing this message first!
Please register or to comment
GitLab Nexedi Edition | About GitLab | About Nexedi | 沪ICP备2021021310号-2 | 沪ICP备2021021310号-7