diff options
| -rw-r--r-- | include/net/ip.h | 1 | ||||
| -rw-r--r-- | net/ipv4/devinet.c | 2 | ||||
| -rw-r--r-- | net/ipv4/igmp.c | 24 | ||||
| -rw-r--r-- | net/ipv4/ip_tunnel.c | 4 |
4 files changed, 19 insertions, 12 deletions
diff --git a/include/net/ip.h b/include/net/ip.h index 9896f46cbbf1..af8addbaa3c1 100644 --- a/include/net/ip.h +++ b/include/net/ip.h @@ -34,6 +34,7 @@ #include <net/flow_dissector.h> #define IPV4_MAX_PMTU 65535U /* RFC 2675, Section 5.1 */ +#define IPV4_MIN_MTU 68 /* RFC 791 */ struct sock; diff --git a/net/ipv4/devinet.c b/net/ipv4/devinet.c index a4573bccd6da..7a93359fbc72 100644 --- a/net/ipv4/devinet.c +++ b/net/ipv4/devinet.c @@ -1428,7 +1428,7 @@ skip: static bool inetdev_valid_mtu(unsigned int mtu) { - return mtu >= 68; + return mtu >= IPV4_MIN_MTU; } static void inetdev_send_gratuitous_arp(struct net_device *dev, diff --git a/net/ipv4/igmp.c b/net/ipv4/igmp.c index d1f8f302dbf3..50448a220a1f 100644 --- a/net/ipv4/igmp.c +++ b/net/ipv4/igmp.c @@ -404,16 +404,17 @@ static int grec_size(struct ip_mc_list *pmc, int type, int gdel, int sdel) } static struct sk_buff *add_grhead(struct sk_buff *skb, struct ip_mc_list *pmc, - int type, struct igmpv3_grec **ppgr) + int type, struct igmpv3_grec **ppgr, unsigned int mtu) { struct net_device *dev = pmc->interface->dev; struct igmpv3_report *pih; struct igmpv3_grec *pgr; - if (!skb) - skb = igmpv3_newpack(dev, dev->mtu); - if (!skb) - return NULL; + if (!skb) { + skb = igmpv3_newpack(dev, mtu); + if (!skb) + return NULL; + } pgr = skb_put(skb, sizeof(struct igmpv3_grec)); pgr->grec_type = type; pgr->grec_auxwords = 0; @@ -436,12 +437,17 @@ static struct sk_buff *add_grec(struct sk_buff *skb, struct ip_mc_list *pmc, struct igmpv3_grec *pgr = NULL; struct ip_sf_list *psf, *psf_next, *psf_prev, **psf_list; int scount, stotal, first, isquery, truncate; + unsigned int mtu; if (pmc->multiaddr == IGMP_ALL_HOSTS) return skb; if (ipv4_is_local_multicast(pmc->multiaddr) && !net->ipv4.sysctl_igmp_llm_reports) return skb; + mtu = READ_ONCE(dev->mtu); + if (mtu < IPV4_MIN_MTU) + return skb; + isquery = type == IGMPV3_MODE_IS_INCLUDE || type == IGMPV3_MODE_IS_EXCLUDE; truncate = type == IGMPV3_MODE_IS_EXCLUDE || @@ -462,7 +468,7 @@ static struct sk_buff *add_grec(struct sk_buff *skb, struct ip_mc_list *pmc, AVAILABLE(skb) < grec_size(pmc, type, gdeleted, sdeleted)) { if (skb) igmpv3_sendpack(skb); - skb = igmpv3_newpack(dev, dev->mtu); + skb = igmpv3_newpack(dev, mtu); } } first = 1; @@ -498,12 +504,12 @@ static struct sk_buff *add_grec(struct sk_buff *skb, struct ip_mc_list *pmc, pgr->grec_nsrcs = htons(scount); if (skb) igmpv3_sendpack(skb); - skb = igmpv3_newpack(dev, dev->mtu); + skb = igmpv3_newpack(dev, mtu); first = 1; scount = 0; } if (first) { - skb = add_grhead(skb, pmc, type, &pgr); + skb = add_grhead(skb, pmc, type, &pgr, mtu); first = 0; } if (!skb) @@ -538,7 +544,7 @@ empty_source: igmpv3_sendpack(skb); skb = NULL; /* add_grhead will get a new one */ } - skb = add_grhead(skb, pmc, type, &pgr); + skb = add_grhead(skb, pmc, type, &pgr, mtu); } } if (pgr) diff --git a/net/ipv4/ip_tunnel.c b/net/ipv4/ip_tunnel.c index fe6fee728ce4..5ddb1cb52bd4 100644 --- a/net/ipv4/ip_tunnel.c +++ b/net/ipv4/ip_tunnel.c @@ -349,8 +349,8 @@ static int ip_tunnel_bind_dev(struct net_device *dev) dev->needed_headroom = t_hlen + hlen; mtu -= (dev->hard_header_len + t_hlen); - if (mtu < 68) - mtu = 68; + if (mtu < IPV4_MIN_MTU) + mtu = IPV4_MIN_MTU; return mtu; } |