@samitouri / QOSamiQemu / commits / 387ee5d2be

hw/net/rocker: Don't keep pointer to h_proto as uint16_t* in OfDpaFlowPktFields

In rocker_of_dpa.c we assume that the h_proto field in an eth_header struct is aligned, and we copy its address into a uint16_t* in the OfDpaFlowPktFields struct which we then dereference later. This isn't a safe assumption; it will also result in compilation failures with gcc if we mark the eth_header struct as QEMU_PACKED because gcc will not let you take the address of an unaligned struct field. Make the h_proto field in OfDpaFlowPktFields a void*, and make all the places where we previously read through that pointer instead use a new accessor function which allows for the possible lack of alignment. (Compare commit 5814c084679 "hw/net/virtio-net.c: Don't assume IP length field is aligned" which fixed a similar problem elsewhere for an ip_header field.) Signed-off-by: Peter Maydell <peter.maydell@linaro.org> Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org> Reviewed-by: Akihiko Odaki <odaki@rsg.ci.i.u-tokyo.ac.jp> Message-ID: <20260212140917.1443253-2-peter.maydell@linaro.org> Signed-off-by: Philippe Mathieu-Daudé <philmd@linaro.org>

Peter Maydell committed Feb 12, 2026 at 14:09 UTC 387ee5d2be300b104c317aa7f86a4c24652c6f3e

1 file changed +12 -7

hw/net/rocker/rocker_of_dpa.c

+12 -7

@@ -143,7 +143,7 @@ typedef struct of_dpa_flow {

143 typedef struct of_dpa_flow_pkt_fields {

144 uint32_t tunnel_id;

145 struct eth_header *ethhdr;

146 - uint16_t *h_proto;

146 + void *h_proto; /* pointer to unaligned uint16_t data */

147 struct vlan_header *vlanhdr;

148 struct ip_header *ipv4hdr;

149 struct ip6_header *ipv6hdr;

@@ -196,6 +196,11 @@ typedef struct of_dpa_group {

196 };

197 } OfDpaGroup;

198

199 +static uint16_t of_dpa_flow_pkt_h_proto(const OfDpaFlowPktFields *fields)

200 +{

201 + return lduw_he_p(fields->h_proto);

202 +}

203 +

204 static int of_dpa_mask2prefix(uint32_t mask)

205 {

206 return 32 - ctz32(ntohl(mask));

@@ -395,7 +400,7 @@ static void of_dpa_flow_pkt_parse(OfDpaFlowContext *fc,

400 fields->ethhdr = iov->iov_base;

401 fields->h_proto = &fields->ethhdr->h_proto;

402

398 - if (ntohs(*fields->h_proto) == ETH_P_VLAN) {

403 + if (ntohs(of_dpa_flow_pkt_h_proto(fields) == ETH_P_VLAN)) {

404 sofar += sizeof(struct vlan_header);

405 if (iov->iov_len < sofar) {

406 DPRINTF("flow_pkt_parse underrun on vlan_header\n");

@@ -405,7 +410,7 @@ static void of_dpa_flow_pkt_parse(OfDpaFlowContext *fc,

410 fields->h_proto = &fields->vlanhdr->h_proto;

411 }

412

408 - switch (ntohs(*fields->h_proto)) {

413 + switch (ntohs(of_dpa_flow_pkt_h_proto(fields))) {

414 case ETH_P_IP:

415 sofar += sizeof(struct ip_header);

416 if (iov->iov_len < sofar) {

@@ -547,7 +552,7 @@ static void of_dpa_term_mac_build_match(OfDpaFlowContext *fc,

552 {

553 match->value.tbl_id = ROCKER_OF_DPA_TABLE_ID_TERMINATION_MAC;

554 match->value.in_pport = fc->in_pport;

550 - match->value.eth.type = *fc->fields.h_proto;

555 + match->value.eth.type = of_dpa_flow_pkt_h_proto(&fc->fields);

556 match->value.eth.vlan_id = fc->fields.vlanhdr->h_tci;

557 memcpy(match->value.eth.dst.a, fc->fields.ethhdr->h_dest,

558 sizeof(match->value.eth.dst.a));

@@ -643,7 +648,7 @@ static void of_dpa_unicast_routing_build_match(OfDpaFlowContext *fc,

648 OfDpaFlowMatch *match)

649 {

650 match->value.tbl_id = ROCKER_OF_DPA_TABLE_ID_UNICAST_ROUTING;

646 - match->value.eth.type = *fc->fields.h_proto;

651 + match->value.eth.type = of_dpa_flow_pkt_h_proto(&fc->fields);

652 if (fc->fields.ipv4hdr) {

653 match->value.ipv4.addr.dst = fc->fields.ipv4hdr->ip_dst;

654 }

@@ -672,7 +677,7 @@ of_dpa_multicast_routing_build_match(OfDpaFlowContext *fc,

677 OfDpaFlowMatch *match)

678 {

679 match->value.tbl_id = ROCKER_OF_DPA_TABLE_ID_MULTICAST_ROUTING;

675 - match->value.eth.type = *fc->fields.h_proto;

680 + match->value.eth.type = of_dpa_flow_pkt_h_proto(&fc->fields);

681 match->value.eth.vlan_id = fc->fields.vlanhdr->h_tci;

682 if (fc->fields.ipv4hdr) {

683 match->value.ipv4.addr.src = fc->fields.ipv4hdr->ip_src;

@@ -713,7 +718,7 @@ static void of_dpa_acl_build_match(OfDpaFlowContext *fc,

718 sizeof(match->value.eth.src.a));

719 memcpy(match->value.eth.dst.a, fc->fields.ethhdr->h_dest,

720 sizeof(match->value.eth.dst.a));

716 - match->value.eth.type = *fc->fields.h_proto;

721 + match->value.eth.type = of_dpa_flow_pkt_h_proto(&fc->fields);

722 match->value.eth.vlan_id = fc->fields.vlanhdr->h_tci;

723 match->value.width = FLOW_KEY_WIDTH(eth.type);

724 if (fc->fields.ipv4hdr) {