The new action inheritdsfield copies the field DS of IPv4 and IPv6 packets into skb->priority. This enables later classification of packets based on the DS field.
Original idea by Jamal Hadi Salim <j...@mojatatu.com> Signed-off-by: Qiaobin Fu <qiaob...@bu.edu> Reviewed-by: Michel Machado <mic...@digirati.com.br> --- Note that the motivation for this patch is found in the following discussion: https://www.spinics.net/lists/netdev/msg501061.html --- diff --git a/include/uapi/linux/tc_act/tc_skbedit.h b/include/uapi/linux/tc_act/tc_skbedit.h index fbcfe27..432ad2f 100644 --- a/include/uapi/linux/tc_act/tc_skbedit.h +++ b/include/uapi/linux/tc_act/tc_skbedit.h @@ -30,9 +30,11 @@ #define SKBEDIT_F_MARK 0x4 #define SKBEDIT_F_PTYPE 0x8 #define SKBEDIT_F_MASK 0x10 +#define SKBEDIT_F_INHERITDSFIELD 0x20 struct tc_skbedit { tc_gen; + __u64 flags; }; enum { diff --git a/net/sched/act_skbedit.c b/net/sched/act_skbedit.c index 6138d1d7..c3e9d03 100644 --- a/net/sched/act_skbedit.c +++ b/net/sched/act_skbedit.c @@ -23,6 +23,9 @@ #include <linux/rtnetlink.h> #include <net/netlink.h> #include <net/pkt_sched.h> +#include <net/ip.h> +#include <net/ipv6.h> +#include <net/dsfield.h> #include <linux/tc_act/tc_skbedit.h> #include <net/tc_act/tc_skbedit.h> @@ -39,8 +42,32 @@ static int tcf_skbedit(struct sk_buff *skb, const struct tc_action *a, tcf_lastuse_update(&d->tcf_tm); bstats_update(&d->tcf_bstats, skb); - if (d->flags & SKBEDIT_F_PRIORITY) - skb->priority = d->priority; + if (d->flags & SKBEDIT_F_INHERITDSFIELD) { + int wlen = skb_network_offset(skb); + + switch (tc_skb_protocol(skb)) { + case htons(ETH_P_IP): + wlen += sizeof(struct iphdr); + if (!pskb_may_pull(skb, wlen)) + goto err; + skb->priority = ipv4_get_dsfield(ip_hdr(skb)) >> 2; + break; + + case htons(ETH_P_IPV6): + wlen += sizeof(struct ipv6hdr); + if (!pskb_may_pull(skb, wlen)) + goto err; + skb->priority = ipv6_get_dsfield(ipv6_hdr(skb)) >> 2; + break; + + default: + goto default_priority; + } + } else { +default_priority: + if (d->flags & SKBEDIT_F_PRIORITY) + skb->priority = d->priority; + } if (d->flags & SKBEDIT_F_QUEUE_MAPPING && skb->dev->real_num_tx_queues > d->queue_mapping) skb_set_queue_mapping(skb, d->queue_mapping); @@ -53,6 +80,10 @@ static int tcf_skbedit(struct sk_buff *skb, const struct tc_action *a, spin_unlock(&d->tcf_lock); return d->tcf_action; + +err: + spin_unlock(&d->tcf_lock); + return TC_ACT_SHOT; } static const struct nla_policy skbedit_policy[TCA_SKBEDIT_MAX + 1] = { @@ -115,6 +146,8 @@ static int tcf_skbedit_init(struct net *net, struct nlattr *nla, } parm = nla_data(tb[TCA_SKBEDIT_PARMS]); + if (parm->flags & SKBEDIT_F_INHERITDSFIELD) + flags |= SKBEDIT_F_INHERITDSFIELD; exists = tcf_idr_check(tn, parm->index, a, bind); if (exists && bind)
