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rtnl: fix parsing/creation of IFLA_AF_SPEC RTA for the AF_BRIDGE family
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Some pecularities in the encoding of the IFLA_AF_SPEC attribute make it
unsuitable for table driven parsing/generation.

To solve this issue, introduce specific datatype handling for IFLA_AF_SPEC
and parse/generate the RTA depending on the address family of the containing
netlink message.

Signed-off-by: Jo-Philipp Wich <jo@mein.io>
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@jow-
jow- committed Jul 3, 2022
1 parent 49056b3 commit 45e8738
Showing 1 changed file with 204 additions and 13 deletions.
217 changes: 204 additions & 13 deletions lib/rtnl.c
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Original file line number Diff line number Diff line change
Expand Up @@ -383,6 +383,7 @@ typedef enum {
DT_LINKINFO,
DT_MULTIPATH,
DT_NUMRANGE,
DT_AFSPEC,
DT_FLAGS,
DT_ENCAP,
DT_SRH,
Expand Down Expand Up @@ -654,23 +655,12 @@ static const uc_nl_nested_spec_t link_attrs_af_spec_inet6_rta = {
}
};

static const uc_nl_nested_spec_t link_attrs_bridge_vinfo_rta = {
.headsize = sizeof(struct bridge_vlan_info),
.nattrs = 2,
.attrs = {
{ IFLA_UNSPEC, "flags", DT_U16, 0, MEMBER(bridge_vlan_info, flags) },
{ IFLA_UNSPEC, "vid", DT_U16, 0, MEMBER(bridge_vlan_info, vid) },
}
};

static const uc_nl_nested_spec_t link_attrs_af_spec_rta = {
.headsize = 0,
.nattrs = 4,
.nattrs = 2,
.attrs = {
{ AF_INET, "inet", DT_NESTED, DF_NO_SET, &link_attrs_af_spec_inet_rta },
{ AF_INET6, "inet6", DT_NESTED, 0, &link_attrs_af_spec_inet6_rta },
{ IFLA_BRIDGE_FLAGS, "bridge_flags", DT_U16, 0, NULL },
{ IFLA_BRIDGE_VLAN_INFO, "bridge_vlan_info", DT_NESTED, DF_MULTIPLE|DF_FLAT, &link_attrs_bridge_vinfo_rta },
}
};

Expand Down Expand Up @@ -727,7 +717,7 @@ static const uc_nl_nested_spec_t link_msg = {
{ IFLA_OPERSTATE, "operstate", DT_U8, 0, NULL },
{ IFLA_NUM_TX_QUEUES, "num_tx_queues", DT_U32, 0, NULL },
{ IFLA_NUM_RX_QUEUES, "num_rx_queues", DT_U32, 0, NULL },
{ IFLA_AF_SPEC, "af_spec", DT_NESTED, 0, &link_attrs_af_spec_rta },
{ IFLA_AF_SPEC, "af_spec", DT_AFSPEC, 0, NULL },
{ IFLA_LINK_NETNSID, "link_netnsid", DT_U32, 0, NULL },
{ IFLA_PROTO_DOWN, "proto_down", DT_BOOL, 0, NULL },
{ IFLA_GROUP, "group", DT_U32, 0, NULL },
Expand Down Expand Up @@ -2343,6 +2333,198 @@ uc_nl_convert_rta_ipopts(const uc_nl_attr_spec_t *spec, struct nl_msg *msg, stru
return opt_obj;
}

static bool
uc_nl_parse_rta_afspec(const uc_nl_attr_spec_t *spec, struct nl_msg *msg, char *base, uc_vm_t *vm, uc_value_t *val)
{
struct rtgenmsg *rtg = nlmsg_data(nlmsg_hdr(msg));
struct bridge_vlan_info vinfo = { 0 };
struct nlattr *nla, *af_nla;
uc_value_t *vi, *vv;
uint32_t num;

nla = nla_reserve(msg, spec->attr, 0);

ucv_object_foreach(val, type, v) {
if (!strcmp(type, "bridge")) {
if (rtg->rtgen_family == AF_UNSPEC)
rtg->rtgen_family = AF_BRIDGE;

vv = ucv_object_get(v, "bridge_flags", NULL);

if (vv) {
if (!uc_nl_parse_u32(vv, &num) || num > 0xffff)
return nla_parse_error(spec, vm, vv, "field bridge.bridge_flags not an integer or out of range 0-65535");

nla_put_u16(msg, IFLA_BRIDGE_FLAGS, num);
}

vv = ucv_object_get(v, "bridge_mode", NULL);

if (vv) {
if (!uc_nl_parse_u32(vv, &num) || num > 0xffff)
return nla_parse_error(spec, vm, vv, "field bridge.bridge_mode not an integer or out of range 0-65535");

nla_put_u16(msg, IFLA_BRIDGE_MODE, num);
}

vi = ucv_object_get(v, "bridge_vlan_info", NULL);

if (vi) {
vv = ucv_object_get(vi, "flags", NULL);

if (vv) {
if (!uc_nl_parse_u32(vv, &num) || num > 0xffff)
return nla_parse_error(spec, vm, vv, "field bridge.bridge_vlan_info.flags not an integer or out of range 0-65535");

vinfo.flags |= num;
}

vv = ucv_object_get(vi, "vid_range", NULL);

if (vv) {
if (ucv_type(vv) != UC_ARRAY || !uc_nl_parse_u32(ucv_array_get(vv, 0), &num) || num > 0xfff)
return nla_parse_error(spec, vm, vv, "field bridge.bridge_vlan_info.vid_range[0] not an integer or out of range 0-4095");

vinfo.flags |= BRIDGE_VLAN_INFO_RANGE_BEGIN;
vinfo.vid = num;
nla_put(msg, IFLA_BRIDGE_VLAN_INFO, sizeof(vinfo), &vinfo);

if (!uc_nl_parse_u32(ucv_array_get(vv, 1), &num) || num > 0xfff)
return nla_parse_error(spec, vm, vv, "field bridge.bridge_vlan_info.vid_range[1] not an integer or out of range 0-4095");

vinfo.flags &= ~BRIDGE_VLAN_INFO_RANGE_BEGIN;
vinfo.flags |= BRIDGE_VLAN_INFO_RANGE_END;
vinfo.vid = num;
nla_put(msg, IFLA_BRIDGE_VLAN_INFO, sizeof(vinfo), &vinfo);
}
else {
vv = ucv_object_get(vi, "vid", NULL);

if (!uc_nl_parse_u32(vv, &num) || num > 0xfff)
return nla_parse_error(spec, vm, vv, "field bridge.bridge_vlan_info.vid not an integer or out of range 0-4095");

vinfo.flags &= ~(BRIDGE_VLAN_INFO_RANGE_BEGIN|BRIDGE_VLAN_INFO_RANGE_END);
vinfo.vid = num;
nla_put(msg, IFLA_BRIDGE_VLAN_INFO, sizeof(vinfo), &vinfo);
}
}
}
else if (!strcmp(type, "inet")) {
af_nla = nla_reserve(msg, AF_INET, link_attrs_af_spec_inet_rta.headsize);

if (!uc_nl_parse_attrs(msg, nla_data(af_nla),
link_attrs_af_spec_inet_rta.attrs,
link_attrs_af_spec_inet_rta.nattrs,
vm, v))
return false;

nla_nest_end(msg, af_nla);
}
else if (!strcmp(type, "inet6")) {
af_nla = nla_reserve(msg, AF_INET6, link_attrs_af_spec_inet6_rta.headsize);

if (!uc_nl_parse_attrs(msg, nla_data(af_nla),
link_attrs_af_spec_inet6_rta.attrs,
link_attrs_af_spec_inet6_rta.nattrs,
vm, v))
return false;

nla_nest_end(msg, af_nla);
}
else {
return nla_parse_error(spec, vm, val, "unknown address family specified");
}
}

nla_nest_end(msg, nla);

return true;
}

static uc_value_t *
uc_nl_convert_rta_afspec(const uc_nl_attr_spec_t *spec, struct nl_msg *msg, struct nlattr **tb, uc_vm_t *vm)
{
struct rtgenmsg *rtg = nlmsg_data(nlmsg_hdr(msg));
uc_value_t *obj, *bridge, *vlan, *vrange;
int16_t vid_start = -1, vid_end = -1;
struct bridge_vlan_info vinfo;
uint16_t vid_flags = 0;
struct nlattr *nla;
int rem;

if (!tb[spec->attr])
return NULL;

obj = ucv_object_new(vm);

if (rtg->rtgen_family == AF_BRIDGE) {
bridge = ucv_object_new(vm);

nla_for_each_attr(nla, nla_data(tb[spec->attr]), nla_len(tb[spec->attr]), rem) {
switch (nla_type(nla)) {
case IFLA_BRIDGE_FLAGS:
if (nla_check_len(nla, sizeof(uint16_t)))
ucv_object_add(bridge, "bridge_flags", ucv_uint64_new(nla_get_u16(nla)));

break;

case IFLA_BRIDGE_MODE:
if (nla_check_len(nla, sizeof(uint16_t)))
ucv_object_add(bridge, "bridge_mode", ucv_uint64_new(nla_get_u16(nla)));

break;

case IFLA_BRIDGE_VLAN_INFO:
if (nla_check_len(nla, sizeof(vinfo))) {
memcpy(&vinfo, nla_data(nla), sizeof(vinfo));

if (vinfo.flags & BRIDGE_VLAN_INFO_RANGE_END)
vid_end = vinfo.vid;
else
vid_start = vinfo.vid;

vid_flags |= (vinfo.flags & ~(BRIDGE_VLAN_INFO_RANGE_BEGIN|BRIDGE_VLAN_INFO_RANGE_END));
}

break;
}
}

if (vid_start != -1) {
vlan = ucv_object_new(vm);

if (vid_end != -1) {
vrange = ucv_array_new_length(vm, 2);

ucv_array_set(vrange, 0, ucv_uint64_new(vid_start));
ucv_array_set(vrange, 1, ucv_uint64_new(vid_end));

ucv_object_add(vlan, "vid_range", vrange);
}
else {
ucv_object_add(vlan, "vid", ucv_uint64_new(vid_start));
}

ucv_object_add(vlan, "flags", ucv_uint64_new(vid_flags));

ucv_object_add(bridge, "bridge_vlan_info", vlan);
}

ucv_object_add(obj, "bridge", bridge);
}
else {
if (!uc_nl_convert_attrs(msg, nla_data(tb[spec->attr]), nla_len(tb[spec->attr]),
link_attrs_af_spec_rta.headsize, link_attrs_af_spec_rta.attrs,
link_attrs_af_spec_rta.nattrs, vm, obj)) {
ucv_put(obj);

return NULL;
}
}

return obj;
}

static bool
uc_nl_parse_rta_u32_or_member(const uc_nl_attr_spec_t *spec, struct nl_msg *msg, char *base, uc_vm_t *vm, uc_value_t *val)
{
Expand Down Expand Up @@ -2754,6 +2936,12 @@ uc_nl_parse_attr(const uc_nl_attr_spec_t *spec, struct nl_msg *msg, char *base,

break;

case DT_AFSPEC:
if (!uc_nl_parse_rta_afspec(spec, msg, base, vm, val))
return false;

break;

case DT_U32_OR_MEMBER:
if (!uc_nl_parse_rta_u32_or_member(spec, msg, base, vm, val))
return false;
Expand Down Expand Up @@ -2997,6 +3185,9 @@ uc_nl_convert_attr(const uc_nl_attr_spec_t *spec, struct nl_msg *msg, char *base
case DT_IPOPTS:
return uc_nl_convert_rta_ipopts(spec, msg, tb, vm);

case DT_AFSPEC:
return uc_nl_convert_rta_afspec(spec, msg, tb, vm);

case DT_U32_OR_MEMBER:
return uc_nl_convert_rta_u32_or_member(spec, msg, base, tb, vm);

Expand Down

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