From f15bc54eeecd86dfba3885aab839cd1f45172a38 Mon Sep 17 00:00:00 2001 From: Lorenzo Bianconi Date: Fri, 22 Dec 2017 15:10:18 +0100 Subject: [PATCH] l2tp: add peer_offset parameter Introduce peer_offset parameter in order to add the capability to specify two different values for payload offset on tx/rx side. If just offset is provided by userspace use it for rx side as well in order to maintain compatibility with older l2tp versions Signed-off-by: Lorenzo Bianconi Signed-off-by: David S. Miller --- include/uapi/linux/l2tp.h | 1 + net/l2tp/l2tp_core.c | 3 ++- net/l2tp/l2tp_core.h | 13 ++++++++++--- net/l2tp/l2tp_debugfs.c | 8 +++++--- net/l2tp/l2tp_netlink.c | 21 ++++++++++++++++++++- 5 files changed, 38 insertions(+), 8 deletions(-) diff --git a/include/uapi/linux/l2tp.h b/include/uapi/linux/l2tp.h index d84ce5c1c9aa..d6fee55dbded 100644 --- a/include/uapi/linux/l2tp.h +++ b/include/uapi/linux/l2tp.h @@ -127,6 +127,7 @@ enum { L2TP_ATTR_UDP_ZERO_CSUM6_TX, /* flag */ L2TP_ATTR_UDP_ZERO_CSUM6_RX, /* flag */ L2TP_ATTR_PAD, + L2TP_ATTR_PEER_OFFSET, /* u16 */ __L2TP_ATTR_MAX, }; diff --git a/net/l2tp/l2tp_core.c b/net/l2tp/l2tp_core.c index 115918ad8eca..6ff64717da1e 100644 --- a/net/l2tp/l2tp_core.c +++ b/net/l2tp/l2tp_core.c @@ -792,7 +792,7 @@ void l2tp_recv_common(struct l2tp_session *session, struct sk_buff *skb, ptr += 2 + offset; } } else - ptr += session->offset; + ptr += session->peer_offset; offset = ptr - optr; if (!pskb_may_pull(skb, offset)) @@ -1785,6 +1785,7 @@ struct l2tp_session *l2tp_session_create(int priv_size, struct l2tp_tunnel *tunn session->lns_mode = cfg->lns_mode; session->reorder_timeout = cfg->reorder_timeout; session->offset = cfg->offset; + session->peer_offset = cfg->peer_offset; session->l2specific_type = cfg->l2specific_type; session->l2specific_len = cfg->l2specific_len; session->cookie_len = cfg->cookie_len; diff --git a/net/l2tp/l2tp_core.h b/net/l2tp/l2tp_core.h index 9534e16965cc..c6fe7cc42a05 100644 --- a/net/l2tp/l2tp_core.h +++ b/net/l2tp/l2tp_core.h @@ -59,7 +59,8 @@ struct l2tp_session_cfg { int debug; /* bitmask of debug message * categories */ u16 vlan_id; /* VLAN pseudowire only */ - u16 offset; /* offset to payload */ + u16 offset; /* offset to tx payload */ + u16 peer_offset; /* offset to rx payload */ u16 l2specific_len; /* Layer 2 specific length */ u16 l2specific_type; /* Layer 2 specific type */ u8 cookie[8]; /* optional cookie */ @@ -86,8 +87,14 @@ struct l2tp_session { int cookie_len; u8 peer_cookie[8]; int peer_cookie_len; - u16 offset; /* offset from end of L2TP header - to beginning of data */ + u16 offset; /* offset from end of L2TP + * header to beginning of + * tx data + */ + u16 peer_offset; /* offset from end of L2TP + * header to beginning of + * rx data + */ u16 l2specific_len; u16 l2specific_type; u16 hdr_len; diff --git a/net/l2tp/l2tp_debugfs.c b/net/l2tp/l2tp_debugfs.c index eb69411bcb47..4cc30b38aba4 100644 --- a/net/l2tp/l2tp_debugfs.c +++ b/net/l2tp/l2tp_debugfs.c @@ -180,8 +180,9 @@ static void l2tp_dfs_seq_session_show(struct seq_file *m, void *v) session->lns_mode ? "LNS" : "LAC", session->debug, jiffies_to_msecs(session->reorder_timeout)); - seq_printf(m, " offset %hu l2specific %hu/%hu\n", - session->offset, session->l2specific_type, session->l2specific_len); + seq_printf(m, " offset %hu peer_offset %hu l2specific %hu/%hu\n", + session->offset, session->peer_offset, + session->l2specific_type, session->l2specific_len); if (session->cookie_len) { seq_printf(m, " cookie %02x%02x%02x%02x", session->cookie[0], session->cookie[1], @@ -228,7 +229,8 @@ static int l2tp_dfs_seq_show(struct seq_file *m, void *v) seq_puts(m, " debug tx-pkts/bytes/errs rx-pkts/bytes/errs\n"); seq_puts(m, " SESSION ID, peer ID, PWTYPE\n"); seq_puts(m, " refcnt cnt\n"); - seq_puts(m, " offset OFFSET l2specific TYPE/LEN\n"); + seq_puts(m, " offset OFFSET peer_offset OFFSET"); + seq_puts(m, " l2specific TYPE/LEN\n"); seq_puts(m, " [ cookie ]\n"); seq_puts(m, " [ peer cookie ]\n"); seq_puts(m, " config mtu/mru/rcvseq/sendseq/dataseq/lns debug reorderto\n"); diff --git a/net/l2tp/l2tp_netlink.c b/net/l2tp/l2tp_netlink.c index 7e9c50125556..d7d4d7a7a54d 100644 --- a/net/l2tp/l2tp_netlink.c +++ b/net/l2tp/l2tp_netlink.c @@ -547,9 +547,25 @@ static int l2tp_nl_cmd_session_create(struct sk_buff *skb, struct genl_info *inf } if (tunnel->version > 2) { - if (info->attrs[L2TP_ATTR_OFFSET]) + if (info->attrs[L2TP_ATTR_PEER_OFFSET]) { + struct nlattr *peer_offset; + + peer_offset = info->attrs[L2TP_ATTR_PEER_OFFSET]; + cfg.peer_offset = nla_get_u16(peer_offset); + } + + if (info->attrs[L2TP_ATTR_OFFSET]) { cfg.offset = nla_get_u16(info->attrs[L2TP_ATTR_OFFSET]); + /* in order to maintain compatibility with older + * versions where offset was used for both tx and + * rx side, update rx side with offset if peer_offset + * is not provided by userspace + */ + if (!info->attrs[L2TP_ATTR_PEER_OFFSET]) + cfg.peer_offset = cfg.offset; + } + if (info->attrs[L2TP_ATTR_DATA_SEQ]) cfg.data_seq = nla_get_u8(info->attrs[L2TP_ATTR_DATA_SEQ]); @@ -763,6 +779,8 @@ static int l2tp_nl_session_send(struct sk_buff *skb, u32 portid, u32 seq, int fl nla_put_string(skb, L2TP_ATTR_IFNAME, session->ifname)) || (session->offset && nla_put_u16(skb, L2TP_ATTR_OFFSET, session->offset)) || + (session->peer_offset && + nla_put_u16(skb, L2TP_ATTR_PEER_OFFSET, session->peer_offset)) || (session->cookie_len && nla_put(skb, L2TP_ATTR_COOKIE, session->cookie_len, &session->cookie[0])) || @@ -903,6 +921,7 @@ static const struct nla_policy l2tp_nl_policy[L2TP_ATTR_MAX + 1] = { [L2TP_ATTR_PW_TYPE] = { .type = NLA_U16, }, [L2TP_ATTR_ENCAP_TYPE] = { .type = NLA_U16, }, [L2TP_ATTR_OFFSET] = { .type = NLA_U16, }, + [L2TP_ATTR_PEER_OFFSET] = { .type = NLA_U16, }, [L2TP_ATTR_DATA_SEQ] = { .type = NLA_U8, }, [L2TP_ATTR_L2SPEC_TYPE] = { .type = NLA_U8, }, [L2TP_ATTR_L2SPEC_LEN] = { .type = NLA_U8, },